Publications of Daniel O. Schmitt
%% Book Sections/Chapters
@misc{fds346142,
Author = {Schmitt, D and Zeininger, A and Granatosky, M},
Title = {Patterns, variability, and flexibility of hand posture
during locomotion in primates.},
Pages = {345-369},
Booktitle = {The Evolution of the Primate Hand Anatomical, Developmental,
Functional, and Paleontological Evidence},
Publisher = {Springer},
Editor = {Kivell, T and Lemelin, P and Richmond, B and Schmitt,
D},
Year = {2016},
Month = {August},
ISBN = {9781493936465},
Abstract = {Labeling the primate hand as “primitive” can seem
counterintuitive given the remarkable dexterity typical of
primates and especially humans. In addition, there is
considerable diversity in primate hand form and use that
allows the exploitation of ...},
Key = {fds346142}
}
@misc{fds201331,
Author = {D. Schmitt},
Title = {Primate Locomotor Evolution: Biomechanical Studies of
Primate Locomotion and Their Implications for Understanding
Primate Neuroethology},
Pages = {31-61},
Booktitle = {Primate Neuroethology},
Publisher = {Oxford},
Address = {London},
Editor = {M. Platt and A. Ghazanfar},
Year = {2012},
Key = {fds201331}
}
@misc{fds201329,
Author = {D. Schmitt},
Title = {Translating Primate Locomotor Biomechanical Variables from
the Laboratory to the Field},
Pages = {7 - 28},
Booktitle = {Primate Locomotion: Linking in-situ and ex-situ
Research},
Publisher = {Springer},
Address = {New York},
Editor = {KD D'Auot and E. Vereecke},
Year = {2010},
ISBN = {1441914196},
Key = {fds201329}
}
@misc{fds44897,
Author = {P. Lemelin and D. Schmitt},
Title = {The origins of grasping and locomotor adaptations in
primates: Comparative and experimental approaches using an
opossum model},
Booktitle = {Primate Origins},
Publisher = {Kluwer},
Editor = {M. Dagosto and M. Ravosa},
Year = {2006},
Key = {fds44897}
}
@misc{fds44934,
Author = {Wall, C.E. and Schmitt, D. and Vinyard, C.J. and Hylander,
W.L.},
Title = {Correlation between transverse mandibular movements and
masseter muscle activity during chewing in Papio
anubis.},
Pages = {277-282},
Booktitle = {Dental Anthropology 2001},
Publisher = {Sheffield Academic Press},
Editor = {A. Brook},
Year = {2005},
Key = {fds44934}
}
@misc{fds44933,
Author = {Gruss, L. T. and Schmitt, D.},
Title = {Bipedalism in Homo Ergaster: An experimental study of the
effects of tibial proportions on locomotor biomechanics. In:
(J Meldrum and C. Hilton eds.) From Biped to Strider: The
emergence of modern human walking, running, and resource
transport.},
Booktitle = {From Biped to Strider: The emergence of modern human
walking, running, and resource transport.},
Publisher = {Kluwer},
Editor = {C. Hilton and J. Meldrum},
Year = {2004},
Key = {fds44933}
}
@misc{fds44932,
Author = {Churchill, S.E. and Schmitt, D.},
Title = {Biomechanics in paleoanthropology: engineering and
experimental approaches to the investigation of behavioral
evolution in the genus Homo.},
Booktitle = {: New Perspectives in Primate Evolution and
Behavior.},
Publisher = {Linnaean Society},
Editor = {C. Harcourt and R. Crompton},
Year = {2003},
Key = {fds44932}
}
%% Papers Published
@article{fds376019,
Author = {Schmitt, D and Sparling, TL and Queen, RM},
Title = {The effect of total ankle arthroplasty on mechanical energy
exchange.},
Journal = {Journal of biomechanics},
Volume = {164},
Pages = {111941},
Year = {2024},
Month = {February},
Abstract = {Total ankle arthroplasty (TAA) is a common surgical solution
for patients with debilitating arthritis of the ankle. Prior
to surgery patients experience high levels of pain and
fatigue and low mechanical energy recovery. It is not known
if TAA restores healthy levels of mechanical energy recovery
in this patient population. This study was designed to
determine whether mechanical energy recovery was restored
following TAA. Ground reaction forces during self-selected
speed walking were collected from patients with symptomatic,
unilateral ankle arthritis (N = 29) before and one and two
years after primary, unilateral TAA. The exchange of
potential (PE) and kinetic (KE) energy was examined, and
direction of change (%congruity) and energy exchange
(%recovery) between the two curves was calculated, with
those subjects with low congruity experiencing high energy
recovery. Linear regressions were used to examine the impact
of walking speed, congruity, and amplitude of the center of
mass (COM) displacement on %recovery, while ANOVA and ANCOVA
models were used to compare energy recovery and congruity
across the three time points. Gender, BMI, and age at
surgery had no effect in this study. TAA improved walking
speed (p = 0.001), increased energy recovery
(p = 0.020), and decreased congruity (p = 0.002), and
these levels were maintained over at least two years.
Differences in congruity were independent of walking speed.
In some patients, especially those who are severely
debilitated by ankle arthritis, TAA is effective in
restoring mechanical energy recovery to levels similar to an
asymptomatic population of a similar age recorded by other
studies.},
Doi = {10.1016/j.jbiomech.2024.111941},
Key = {fds376019}
}
@article{fds370862,
Author = {Boulinguez-Ambroise, G and Dunham, N and Phelps, T and Mazonas, T and Nguyen, P and Bradley-Cronkwright, M and Boyer, DM and Yapuncich, GS and Zeininger, A and Schmitt, D and Young, JW},
Title = {Jumping performance in tree squirrels: Insights into primate
evolution.},
Journal = {J Hum Evol},
Volume = {180},
Pages = {103386},
Year = {2023},
Month = {July},
Abstract = {Morphological traits suggesting powerful jumping abilities
are characteristic of early crown primate fossils. Because
tree squirrels lack certain 'primatelike' grasping features
but frequently travel on the narrow terminal branches of
trees, they make a viable extant model for an early stage of
primate evolution. Here, we explore biomechanical
determinants of jumping performance in the arboreal Eastern
gray squirrel (Sciurus carolinensis, n = 3) as a greater
understanding of the biomechanical strategies that squirrels
use to modulate jumping performance could inform theories of
selection for increased jumping ability during early primate
evolution. We assessed vertical jumping performance by using
instrumented force platforms upon which were mounted
launching supports of various sizes, allowing us to test the
influence of substrate diameter on jumping kinetics and
performance. We used standard ergometric methods to quantify
jumping parameters (e.g., takeoff velocity, total
displacement, peak mechanical power) from force platform
data during push-off. We found that tree squirrels display
divergent mechanical strategies according to the type of
substrate, prioritizing force production on flat ground
versus center of mass displacement on narrower poles. As
jumping represents a significant part of the locomotor
behavior of most primates, we suggest that jumping from
small arboreal substrates may have acted as a potential
driver of the selection for elongated hindlimb segments in
primates, allowing the center of mass to be accelerated over
a longer distance-and thereby reducing the need for high
substrate reaction forces.},
Doi = {10.1016/j.jhevol.2023.103386},
Key = {fds370862}
}
@article{fds371432,
Author = {Queen, RM and Schmitt, D},
Title = {Reflections on Presurgical and Postsurgical Gait Mechanics
After 50 Years of Total Ankle Arthroplasty and Perspectives
on the Next Decade of Advancement.},
Journal = {Foot and ankle clinics},
Volume = {28},
Number = {1},
Pages = {99-113},
Year = {2023},
Month = {March},
Abstract = {Although not the most prevalent form of lower limb
pathology, ankle arthritis is one of the most painful and
life-limiting forms of arthritis. Developing from overuse
and various traumatic injuries, the effect of ankle
arthritis on gait mechanics and effective treatment options
for ankle arthritis remain an area of extensive inquiry.
Although nonsurgical options are common (physical therapy,
limited weight-bearing, and steroidal injections), surgical
options are popular with patients. Fusion remains a common
approach to stabilize the joint and relieve pain. However,
starting in the early 1970s, total ankle arthroplasty was
proposed as an alternative to fusion.},
Doi = {10.1016/j.fcl.2022.10.005},
Key = {fds371432}
}
@article{fds369333,
Author = {Garrett, SG and Simmons Muckler and VC and Schmitt, DO and Hartwell, EH and Thompson, JA and Falyar, CR},
Title = {Improving Anesthesia Providers' Needle Cricothyrotomy
Success With Ultrasound-Guidance: A Cadave Quality
Improvement Project.},
Journal = {AANA journal},
Volume = {91},
Number = {1},
Pages = {15-21},
Year = {2023},
Month = {February},
Abstract = {Difficult and failed airway management remains a significant
cause of anesthesia-related morbidity and mortality. Failed
airway management guidelines include performing a
cricothyrotomy as a final step. Correct identification of
the cricothyroid membrane (CTM) is essential for safe and
accurate cricothyrotomy execution. Ten certified registered
nurse anesthetists were assessed for ultrasound-guided (USG)
needle cricothyrotomy competency following an online and
hands-on education session using a human cadaver and then
assessed 60 days later, without additional education or
preparation. Both knowledge and confidence improved
significantly when assessed immediately after education (P <
.05) and were maintained when assessed 60 days later.
Overall skill performance declined slightly from
post-training although the decline was not statistically
significant (P = .373). Overall needle placement time and
distance from the CTM improved, despite improper transducer
and image orientation by most participants. A one-hour
hybrid educational program can significantly improve
ultrasound and cricothyrotomy knowledge and confidence for
60 days. Transducer orientation may not be a significant
contributor to performing proper USG needle
cricothyrotomy.},
Key = {fds369333}
}
@article{fds366695,
Author = {Larsen, RJ and Queen, RM and Schmitt, D},
Title = {Adaptive locomotion: Foot strike pattern and limb mechanical
stiffness while running over an obstacle.},
Journal = {Journal of biomechanics},
Volume = {143},
Pages = {111283},
Year = {2022},
Month = {October},
Abstract = {Previous studies of level running suggest runners adjust
foot strike to control leg stiffness. This study aimed to
determine how runners adjusted mechanical stiffness and foot
strike prior to, during, and after a drop in surface height.
Ten healthy subjects (5 male, 5 female; 24.32 ± 5.0 years)
were video recorded as they ran on an outdoor path with a
single drop in surface height (12.5 cm). Foot strike was
recorded, while subject velocity, duty factor (DF),
normalized maximum ground reaction force (GRF<sub>bw</sub>),
vertical hip displacement (Δy), leg compression (ΔL),
vertical (K<sub>vert</sub>) and leg stiffness
(K<sub>leg</sub>), touchdown (TD) and takeoff angle (TO),
and flight (T<sub>f</sub>) and contact time (T<sub>c</sub>)
were calculated. Compared to the step before the drop,
T<sub>f</sub>, GRF<sub>bw</sub>, K<sub>vert</sub>,
K<sub>leg</sub>, and TO increased, while T<sub>c</sub>, DF,
Δy, ΔL, and TD decreased in the step after the drop.
Across trials, runners had either consistent or variable
foot strike patterns. Runners using a consistent pattern
most often shifted from rear to fore-foot strike in the
steps before and after the drop, while those with a variable
pattern showed less dramatic shifts. All parameters, except
TD, were significantly different (p < 0.04) based on foot
strike pattern, and comparisons between steps before and
after the drop (except TD) were significantly different
(p < 0.004). Runners with a variable foot strike pattern
experienced smaller shifts within mechanical parameters when
traveling over the drop, suggesting these runners may be
able to stabilize limb mechanics on interrupted
surfaces.},
Doi = {10.1016/j.jbiomech.2022.111283},
Key = {fds366695}
}
@article{fds355598,
Author = {Hill, CN and Reed, W and Schmitt, D and Arent, SM and Sands, LP and Queen,
RM},
Title = {Factors contributing to racial differences in gait mechanics
differ by sex.},
Journal = {Gait & posture},
Volume = {95},
Pages = {277-283},
Year = {2022},
Month = {June},
Abstract = {<h4>Background</h4>Racial differences in gait mechanics have
been recently reported, but we don't know what factors may
drive differences in gait and whether these factors are
innate or modifiable. The answers to those questions will
inform both basic research and clinical interventions and
outcomes.<h4>Research question</h4>Do anthropometric,
strength, and health status measures explain racial
differences in gait between African Americans (AA) and white
Americans (WA)?<h4>Methods</h4>Venous blood samples,
anthropometric measures, lower extremity strength, and an
assessment of health status were collected from 92
participants (18-30 years old) as part of an Institutional
Review Board-approved study. 3D motion capture and force
plate data were recorded during 7 walking trials at set
regular (1.35 m/s) and fast (1.6 m/s) speeds. Racial
differences in gait were identified at both speeds.
Correlations between anthropometric, strength, and health
status independent variables and outcome measures were
computed after stratifying data by sex. Stepwise linear
regression models evaluated whether the inclusion of
anthropometric, strength, and health status independent
variables explained racial effects.<h4>Results</h4>In males,
no racial differences in gait were explained by independent
variables. Q-angle and ankle dorsiflexion strength accounted
for racial differences in self-selected walking speed in
females. Racial differences in ankle plantarflexion angle
were explained by ankle plantarflexion strength
differences.<h4>Significance</h4>Factors that explain racial
differences in gait in females were both innate and
modifiable. These data make clear that it is important to
include racially diverse normative gait databases in
research studies. These results also identify potential
intervention targets aimed at reducing racial health
disparities.},
Doi = {10.1016/j.gaitpost.2021.02.024},
Key = {fds355598}
}
@article{fds363367,
Author = {Grider-Potter, N and Zeininger, A and Schmitt, D and Snyder, M and McGrosky, A},
Title = {Energetic costs of hindlimb-dominated locomotion in sifakas
(Propithecus verreauxi).},
Journal = {FASEB J},
Volume = {36 Suppl 1},
Year = {2022},
Month = {May},
Abstract = {Human bipedal locomotion is unique, requiring a suite of
musculoskeletal adaptations that were acquired gradually
throughout hominin evolution. For example, lordotic lumbar
spines move the center of mass over the hip joint and
resists axial compression, short, laterally-oriented iliac
blades increase the leverage of the hip extensors and
abductors, and the adducted hallux facilitates weight
transfer during a propulsive toe-off. Sifakas and other
primates occasionally move bipedally in the wild, especially
in terrestrial settings, but because they lack specialized
anatomy, bipedal locomotion should be less efficient. In
this study we test the hypothesis that energy costs differ
among sifaka locomotor modes and predict that terrestrial
bipedal locomotion is associated with greater energy
expenditure than their more habitual mode of arboreal
locomotion, vertical clinging and leaping. Bipedal (n=77)
and vertical clinging and leaping (n=74) gait cycles were
filmed in nine sifakas at the Duke Lemur Center. Locomotor
data (stride length, peak body height of the cycle, and
velocity) were measured from these videos using ImageJ and
used to calculate energy expenditure using published
equations. Linear mixed models were used to statistically
test the differences in energy expenditure between locomotor
modes while accounting for the effects of velocity and
repeatedly measuring the same individuals. Results
demonstrate that the cost of bipedalism is significantly
greater than that of vertical clinging and leaping
(p<0.0001). This result supports the idea that the locomotor
adaptations in the hominin musculoskeletal system reduce the
cost of locomoting bipedally. Furthermore, because sifakas
rely on bipedal locomotion in terrestrial settings, these
results have conservation implications for understanding the
energetic demands of sifaka locomotion in deforested
habitats.},
Doi = {10.1096/fasebj.2022.36.S1.R4619},
Key = {fds363367}
}
@article{fds363229,
Author = {Hill, CN and Schmitt, D and Reed, W and Arent, SM and Sands, LP and Queen,
RM},
Title = {Racial differences in running and landing measures
associated with injury risk vary by sex},
Journal = {Sports Biomechanics},
Year = {2022},
Month = {January},
Abstract = {It is unknown whether running and landing mechanics differ
between racial groups despite injury disparities between
African Americans (AA) and white Americans (WA). This study
aimed to identify potential racial differences in running
and landing mechanics and understand whether anthropometric,
strength, and health status factors contribute to these
differences. Venous blood samples, anthropometry,
lower-extremity strength, and health status assessments were
collected (n = 84, 18–30y). Three-dimensional motion
capture and force plate data were recorded during 7 running
and 7 drop vertical jump trials. Racial effects were
determined, and regression models evaluated explanatory
factors. AA females ran with longer stance times
(p = 0.003) than WA females, while AA males ran with
smaller loading rates (p = 0.046) and larger peak vertical
ground reaction forces (p = 0.036) than WA males. Frontal
plane knee range of motion during landing was greater in AA
females (p = 0.033) than WA females; larger waist
circumference and weaker knee extension strength accounted
for this significance. Although outcome measures were
associated with physiologic, anthropometric, and activity
measures, their explanatory power for race was ambiguous,
except for knee range of motion in females. Modifiable
factors explaining racial effects during landing in females
are potential intervention targets to reduce racial health
disparities in running and landing injuries.},
Doi = {10.1080/14763141.2022.2056075},
Key = {fds363229}
}
@article{fds358748,
Author = {Tasnim, N and Schmitt, D and Zeininger, A},
Title = {Effects of human variation on foot and ankle pain in rural
Madagascar.},
Journal = {American journal of physical anthropology},
Volume = {176},
Number = {2},
Pages = {308-320},
Year = {2021},
Month = {October},
Abstract = {<h4>Objectives</h4>Foot and ankle dysfunction in
barefoot/minimally shod populations remains understudied.
Although factors affecting musculoskeletal pain in Western
populations are well-studied, little is known about how
types of work, gender, and body shape influence bone and
joint health in non-Western and minimally shod communities.
This study examines the effect of human variation on
locomotor disability in an agrarian community in
Madagascar.<h4>Materials and methods</h4>Foot measurements
were collected along with height, weight, age, and
self-report data on daily activity and foot and ankle pain
from 41 male and 48 female adults. A short form revised foot
function index (FFI-R), that measures functional disability
related to foot pain, was calculated. Raw and normalized
foot measurements were compared by gender and used in a
multiple linear regression model to determine predictors of
FFI-R.<h4>Results</h4>Compared to men, women reported higher
FFI-R scores (p = 0.014), spent more time on their feet
(p = 0.019), and had higher BMIs (p = 0.0001). For their
weight, women had significantly smaller and narrower feet
than men. Bimalleolar breadth (p = 0.0005) and foot length
(p = 0.0223) standardized by height, time spent on feet
(p = 0.0102), ankle circumference standardized by weight
(p = 0.0316), and age (p = 0.0090) were significant
predictors of FFI-R score.<h4>Discussion</h4>Our findings
suggest that human variation in anatomical and behavioral
patterns serve as significant explanations for increased
foot and ankle pain in women in this non-Western rural
population. Foot and ankle pain were prevalent at similar
levels to those in industrialized populations, indicating
that research should continue to examine its effect on
similar barefoot/minimally shod communities.},
Doi = {10.1002/ajpa.24392},
Key = {fds358748}
}
@article{fds352382,
Author = {Zeininger, A and Schmitt, D and Hughes-Oliver, C and Queen,
RM},
Title = {The effect of ankle osteoarthritis and total ankle
arthroplasty on center of pressure position.},
Journal = {Journal of orthopaedic research : official publication of
the Orthopaedic Research Society},
Volume = {39},
Number = {6},
Pages = {1245-1252},
Year = {2021},
Month = {June},
Abstract = {Total ankle arthroplasty (TAA) is a common surgical approach
for patients with end-stage ankle osteoarthritis (OA).
However, very little is known about the path of the center
of pressure (COP) of the foot, and thus important aspects of
load transfer, muscle mechanical advantage, and balance, in
patients before or after surgery. The objective of this
study was to trace the pathway of the COP under the foot in
patients with symptomatic ankle OA, comparing asymmetry
between affected and unaffected limbs. From force plate
data, proximodistal and mediolateral positions of the COP
beneath the foot were calculated and compared for the
affected and unaffected foot in patients with unilateral
ankle OA (N = 93) before and after TAA. Gender and age
at surgery had little or no effect in this study. Patients
with ankle OA had minimal COP position asymmetry before
surgery, and this asymmetry was reduced following surgery.
Before surgery, patients had a slower walking speed and a
shorter path of the COP which began relatively distal to the
heel and ended relatively proximal to the hallux. TAA
increased the proximodistal distance the COP traveled under
both the unaffected and affected foot, a pattern that was
maintained for over 2-year postsurgery. TAA allows patients
with ankle OA to maintain a longer COP path than they had
before surgery on both sides that is closer to that reported
for unaffected individuals, extending effectively from the
heel to the hallux, potentially improving pedal
mechanics.},
Doi = {10.1002/jor.24857},
Key = {fds352382}
}
@article{fds355908,
Author = {Clark, CM and Morgan, BT and Schmitt, D and Harman, RJ and Goode,
V},
Title = {Improving Emergency Cricothyroidotomies: Simulation-Based
Training for Critical Care Providers.},
Journal = {Critical care nursing quarterly},
Volume = {44},
Number = {2},
Pages = {203-213},
Year = {2021},
Month = {April},
Abstract = {This article discusses skill proficiency of providers
related to emergency cricothyroidotomies. Various techniques
to improve procedural skills were studied. Accurate
identification of the cricothyroid membrane via palpation
remained consistently inadequate. High-fidelity simulation
including the use of human cadavers may be the preferred
method of skill training for crisis management. The authors
emphasize that additional research is needed regarding a
method for rapid cricothyroid membrane identification as
well as needle cricothyroidotomy versus surgical airway on
cadavers. More consistent training will enable emergency
care providers to perform this rare but lifesaving
skill.},
Doi = {10.1097/cnq.0000000000000354},
Key = {fds355908}
}
@article{fds351241,
Author = {Peebles, AT and Carroll, MM and Socha, JJ and Schmitt, D and Queen,
RM},
Title = {Validity of Using Automated Two-Dimensional Video Analysis
to Measure Continuous Sagittal Plane Running
Kinematics.},
Journal = {Annals of biomedical engineering},
Volume = {49},
Number = {1},
Pages = {455-468},
Year = {2021},
Month = {January},
Abstract = {Two-dimensional video analysis is commonly used to assess
kinematics when three-dimensional motion capture is
unavailable. However, videos are often assessed using manual
digitization, which limits the ability to extract outcomes
that require continuous data. Here, we introduced a method
to collect continuous kinematic data in 2D using an
inexpensive camera and an open-source automated marker
tracking program. We tested the validity of this method by
comparing 2D video analysis to 3D motion capture for
measuring sagittal-plane running kinematics. Twenty
uninjured participants ran on a treadmill for 1-min while
lower extremity kinematics were collected simultaneously in
3D using a motion capture system and in 2D using a single
digital camera, both at 120 Hz. Knee, ankle, and foot angle
at contact, peak knee flexion, knee flexion excursion, and
knee-ankle flexion vector coding variability were computed
using both the 3D and 2D kinematic data, and were compared
using intraclass correlation coefficients and Bland-Altman
plots. The agreement between collection methods was
excellent for foot angle at contact and knee flexion
excursion, good for ankle and knee angle at contact and
knee-ankle vector coding variability, and moderate for peak
knee flexion. However, Bland-Altman plots revealed
significant differences between the 2D and 3D collection
methods, which varied across study participants. These
low-cost methods could be useful for collecting continuous
sagittal plane running kinematics in non-laboratory
settings.},
Doi = {10.1007/s10439-020-02569-y},
Key = {fds351241}
}
@article{fds368052,
Author = {Queen, RM and Schmitt, D},
Title = {Sex-Specific Difference in Dynamic Balance Following Total
Hip Replacement.},
Journal = {Innovation in aging},
Volume = {5},
Number = {2},
Pages = {igab019},
Year = {2021},
Month = {January},
Abstract = {<h4>Background and objectives</h4>Total hip arthroplasty
(THA) is a common surgical procedure in older adults (65
years or older). THA has high patient satisfaction, but
little is known about balance and mobility limitations after
surgery and if outcomes are sex-specific. This study was
aimed to evaluate post-THA asymmetry during unilateral
standing and a dynamic balance and reach test and test the
hypotheses that balance performance would be decreased on
the surgical limb and that balance deficits would be greater
in women than in men.<h4>Research design and
methods</h4>Primary, unilateral THA (70 male, 57 female)
patients completed a bilateral 10-s single-leg stance test.
Sixty male but only 34 female participants could maintain
unilateral balance for 10 s or greater. The cohort who
successfully completed the 10-s single-limb stance test then
completed a Lower Quarter Y-Balance Test in which the
maximum anterior (ANT), posteromedial (PM), and
posterolateral reach distances were obtained bilaterally and
used to calculate the asymmetry score. All variables were
compared using a mixed-model repeated-measures analysis of
variance (sex by limb), while independent samples <i>t</i>
tests were used to assess sex-specific asymmetry.<h4>Results</h4>Women
failed single-leg stance at a higher rate than men (85.7% vs
59.6%; <i>p =</i> .001). Reach distance was different
between limbs for all reach directions (<i>p</i> < .004)
with greater reach distance on the nonoperative limb for all
patients. Men had a greater reach distance in the ANT (<i>p
=</i> .004) and PM (<i>p =</i> .006) directions.<h4>Discussion
and implications</h4>These results indicate that post-THA,
the operative limb and female patients have greater balance
limitations. These results are novel and reveal sex-specific
patterns that emphasize the need for sex-specific
postoperative rehabilitation programs to improve long-term
outcomes, especially in older adults with muscle weakness
and balance deficits.},
Doi = {10.1093/geroni/igab019},
Key = {fds368052}
}
@article{fds352633,
Author = {Hill, CN and Reed, W and Schmitt, D and Sands, LP and Queen,
RM},
Title = {Racial differences in gait mechanics.},
Journal = {Journal of biomechanics},
Volume = {112},
Pages = {110070},
Year = {2020},
Month = {November},
Abstract = {The effect of race has rarely been investigated in
biomechanics studies despite racial health disparities in
the incidence of musculoskeletal injuries and disease,
hindering both treatment and assessment of rehabilitation.
The purpose of this study was to test the hypothesis that
racial differences in gait mechanics exist between African
Americans (AA) and white Americans (WA). Ninety-two
participants (18-30 years old) were recruited with equal
numbers in each racial group and sex. Self-selected walking
speed was measured for each participant. 3D motion capture
and force plate data were recorded during 7 walking trials
at regular and fast set speeds. Step length, step width,
peak vertical ground reaction force, peak hip extension,
peak knee flexion, and peak ankle plantarflexion were
computed for all trials at both set speeds. Multivariate and
post-hoc univariate ANOVA models were fit to determine main
and interaction effects of sex and race (SPSS V26,
α = 0.05). Self-selected walking speed was slower in AA
(p = 0.004, ƞ<sub>p</sub><sup>2</sup> = 0.088). No
significant interactions between race and sex were
identified. Males took longer steps (regular: p < 0.001,
ƞ<sub>p</sub><sup>2</sup> = 0.288, fast: p < 0.001,
ƞ<sub>p</sub><sup>2</sup> = 0.193) and had larger peak
knee flexion (regular: p = 0.007, ƞ<sub>p</sub><sup>2</sup> = 0.081,
fast: p < 0.001, ƞ<sub>p</sub><sup>2</sup> = 0.188) and
ankle plantarflexion angles (regular: p = 0.050,
ƞ<sub>p</sub><sup>2</sup> = 0.044, fast: p = 0.049,
ƞ<sub>p</sub><sup>2</sup> = 0.044). Peak ankle
plantarflexion angle (regular: p = 0.012,
ƞ<sub>p</sub><sup>2</sup> = 0.071, fast: p < 0.001,
ƞ<sub>p</sub><sup>2</sup> = 0.137) and peak hip extension
angle during fast walking (p = 0.007, ƞ<sub>p</sub><sup>2</sup> = 0.083)
were smaller in AA. Equivalency in gait measures between
racial groups should not be assumed. Racially diverse study
samples should be prioritized in the development of future
research and individualized treatment protocols.},
Doi = {10.1016/j.jbiomech.2020.110070},
Key = {fds352633}
}
@article{fds350616,
Author = {Zeininger, A and Schmitt, D and Wunderlich, RE},
Title = {Mechanics of heel-strike plantigrady in African
apes.},
Journal = {Journal of human evolution},
Volume = {145},
Pages = {102840},
Year = {2020},
Month = {August},
Abstract = {The initiation of a walking step with a heel strike is a
defining characteristic of humans and great apes but is
rarely found in other mammals. Despite the considerable
importance of heel strike to an understanding of human
locomotor evolution, no one has explicitly tested the
fundamental mechanical question of why great apes use a heel
strike. In this report, we test two hypotheses (1) that heel
strike is a function of hip protraction and/or knee
extension and (2) that short-legged apes with a midfoot that
dorsiflexes at heel lift and long digits for whom
digitigrady is not an option use heel-strike plantigrady.
This strategy increases hip translation while potentially
moderating the cost of redirecting the center of mass
('collisional costs') during stance via rollover along the
full foot from the heel to toes. We quantified hind limb
kinematics and relative hip translation in ten species of
primates, including lemurs, terrestrial and arboreal
monkeys, chimpanzees, and gorillas. Chimpanzees and gorillas
walked with relatively extended knees but only with
moderately protracted hips or hind limbs, partially
rejecting the first hypothesis. Nonetheless, chimpanzees
attained relative hip translations comparable with those of
digitigrade primates. Heel-strike plantigrady may be a
natural result of a need for increased hip translations when
forelimbs are relatively long and digitigrady is
morphologically restricted. In addition, foot rollover from
the heel to toe in large, short-legged apes may reduce
energetic costs of redirecting the center of mass at the
step-to-step transition as it appears to do in humans. Heel
strike appears to have been an important mechanism for
increasing hip translation, and possibly reducing energetic
costs, in early hominins and was fundamental to the
evolution of the modern human foot and human
bipedalism.},
Doi = {10.1016/j.jhevol.2020.102840},
Key = {fds350616}
}
@article{fds348623,
Author = {Queen, R and Dickerson, L and Ranganathan, S and Schmitt,
D},
Title = {A novel method for measuring asymmetry in kinematic and
kinetic variables: The normalized symmetry
index.},
Journal = {Journal of biomechanics},
Volume = {99},
Pages = {109531},
Year = {2020},
Month = {January},
Abstract = {Gait and movement asymmetries are important variables for
assessing locomotor mechanics in humans and other animals
and as a predictor of injury risk and success of clinical
interventions. The four indices used most often to assess
symmetry are not well designed for different variable types,
perform poorly when presented with cases of high asymmetry
or when variables are of low magnitude, and are easily
influenced by small variation in the signal. The purpose of
the present study was to test the performance of these
indices on previously unpublished data on ACL-R patients and
to propose a new index to resolve some of these limitations.
The performance of four currently used indices and a new
index-the Normalized Symmetry Index (NSI), which is scaled
to the range of variables being tested across multiple
trials-were compared using force and angular data on
participants who had undergone anterior cruciate ligament
reconstruction and healthy controls. The NSI performed well
compared to all other indices with all variables and had the
additional benefit of returning values that range from 0%
(full symmetry) to ±100% (full asymmetry). Therefore, the
NSI can serve as a universal index for assessing asymmetry
in humans, nonhuman animal models, and in a clinical context
for assessing risk for injury and clinical
outcomes.},
Doi = {10.1016/j.jbiomech.2019.109531},
Key = {fds348623}
}
@article{fds349709,
Author = {Cullen, MM and Schmitt, D and Granatosky, MC and Wall, CE and Platt, M and Larsen, R},
Title = {Gaze-behaviors of runners in a natural, urban running
environment.},
Journal = {PloS one},
Volume = {15},
Number = {5},
Pages = {e0233158},
Year = {2020},
Month = {January},
Abstract = {Gaze-tracking techniques have advanced our understanding of
visual attention and decision making during walking and
athletic events, but little is known about how vision
influences behavior during running over common, natural
obstacles. This study tested hypotheses about whether
runners regularly collect visual information and pre-plan
obstacle clearance (feedforward control), make
improvisational adjustments (online control), or some
combination of both. In this study, the gaze profiles of 5
male and 5 female runners, fitted with a telemetric
gaze-tracking device, were used to identify the frequency of
fixations on an obstacle during a run. Overall, participants
fixated on the obstacle 2.4 times during the run, with the
last fixation occurring on average between 40% and 80% of
the run, suggesting runners potentially shifted from a
feedforward planning strategy to an online control strategy
during the late portions of the running trial. A negative
association was observed between runner velocity and average
number of fixations. Consistent with previous studies on
visual strategies used during walking, our results indicate
that visual attentiveness is part of an important
feedforward strategy for runners allowing them to safely
approach an obstacle. Thus, visual obstacle attention is a
key factor in the navigation of complex, natural landscapes
while running.},
Doi = {10.1371/journal.pone.0233158},
Key = {fds349709}
}
@article{fds346141,
Author = {Abbott, EM and Nezwek, T and Schmitt, D and Sawicki,
GS},
Title = {Hurry Up and Get Out of the Way! Exploring the Limits of
Muscle-Based Latch Systems for Power Amplification.},
Journal = {Integrative and comparative biology},
Volume = {59},
Number = {6},
Pages = {1546-1558},
Year = {2019},
Month = {December},
Abstract = {Animals can amplify the mechanical power output of their
muscles as they jump to escape predators or strike to
capture prey. One mechanism for amplification involves
muscle-tendon unit (MT) systems in which a spring element
(series elastic element [SEE]) is pre-stretched while held
in place by a "latch" that prevents immediate transmission
of muscle (or contractile element, CE) power to the load. In
principle, this storage phase is followed by a triggered
release of the latch, and elastic energy released from the
SEE enables power amplification (PRATIO=PLOAD/PCE,max >1.0),
whereby the peak power delivered from MT to the load exceeds
the maximum power limit of the CE in isolation. Latches
enable power amplification by increasing the muscle work
generated during storage and reducing the duration over
which that stored energy is released to power a movement.
Previously described biological "latches" include: skeletal
levers, anatomical triggers, accessory appendages, and even
antagonist muscles. In fact, many species that rely on
high-powered movements also have a large number of muscles
arranged in antagonist pairs. Here, we examine whether a
decaying antagonist force (e.g., from a muscle) could be
useful as an active latch to achieve controlled energy
transmission and modulate peak output power. We developed a
computer model of a frog hindlimb driven by a compliant MT.
We simulated MT power generated against an inertial load in
the presence of an antagonist force "latch" (AFL) with
relaxation time varying from very fast (10 ms) to very slow
(1000 ms) to mirror physiological ranges of antagonist
muscle. The fastest AFL produced power amplification
(PRATIO=5.0) while the slowest AFL produced power
attenuation (PRATIO=0.43). Notably, AFLs with relaxation
times shorter than ∼300 ms also yielded greater power
amplification (PRATIO>1.20) than the system driving the same
inertial load using only an agonist MT without any AFL.
Thus, animals that utilize a sufficiently fast relaxing AFL
ought to be capable of achieving greater power output than
systems confined to a single agonist MT tuned for maximum
PRATIO against the same load.},
Doi = {10.1093/icb/icz141},
Key = {fds346141}
}
@article{fds345670,
Author = {Queen, RM and Campbell, JC and Schmitt, D},
Title = {Gait Analysis Reveals that Total Hip Arthroplasty Increases
Power Production in the Hip During Level Walking and Stair
Climbing.},
Journal = {Clinical orthopaedics and related research},
Volume = {477},
Number = {8},
Pages = {1839-1847},
Year = {2019},
Month = {August},
Abstract = {<h4>Background</h4>total hip arthroplasty (THA) is
associated with decreased pain and improved function,
including increased walking speed, but it does not always
improve overall joint mechanics during activities of daily
living such as level walking and stair climbing. The hip's
ability to generate power to move and allow for smooth and
efficient forward motion is critical to success after
surgery. Although osteoarthritis (OA) of the hip limits the
power of the affected joint, it is not known whether other
joints in the affected limb or in the contralateral limb
need to produce more power to compensate. Additionally, it
is not known whether alterations in the production of power
before and after surgery are gender-specific.<h4>Questions/purposes</h4>(1)
Is there a change in the power production of the bilateral
ankles, knees, and hips during level walking before and
after patients undergo unilateral THA, and are there
important gender-specific differences in these findings? (2)
How do these findings differ for stair climbing?<h4>Methods</h4>Three-dimensional
motion and ground reaction force data were collected for 13
men and 13 women who underwent primary, unilateral THA. This
was a secondary analysis of previously collected data on
gait mechanics from 60 patients who underwent THA. In the
initial study, patients were included if they were scheduled
to undergo a primary, unilateral THA within 4 weeks of the
study and were able to walk without an assistive device.
Patients were recruited from the practices of four surgeons
at a single institution from 2008 to 2011. Patients were
included in the current study if they were enrolled in the
previous study, attended all three assessment visits
(preoperative and 6 weeks and 1 year postoperative), and,
during the preoperative visit, were able to walk without
using an assistive device and climb stairs without using a
handrail. Patients walked and ascended stairs at a
self-selected speed at the three assessment visits. The
power of each ankle, knee, or hip was calculated in Visual
3D using kinematic and kinetic data collected using motion
capture. Power for each joint was normalized to the total
power of the bilateral lower limbs by dividing the
individual joint power by the total lower-extremity joint
power. A mixed-model repeated-measures ANOVA was used to
determine differences in normalized joint power for the
ankle, knee, and hip, based on gender, limb (surgical-side
versus nonsurgical-side) and timepoint (preoperative and 6
weeks and 1 year postoperative).<h4>Results</h4>Surgical-side
absolute (preoperative: -0.2 ± 0.2 [CI, -0.3 to -0.2], 1
year postoperative: -0.5 ± 0.3 [CI, -0.6 to - 0.5]; p <
0.001) and normalized (preoperative: 0.05 ± 0.04 [CI,
0.03-0.06], 1 year postoperative: 0.08 ± 0.04 [CI,
0.06-0.09]; p = 0.020) hip power production increased during
walking. Surgical-side absolute (preoperative: 1.1 ± 0.3
[CI, 1.0-1.3], 1 year postoperative: 1.6 ± 0.2 [CI,
1.3-2.0]; p = 0.005) and normalized (preoperative: 0.16 ±
0.04 [CI, 0.14-0.18], 1 year postoperative: 0.21 ± 0.06
[CI, 0.18-0.24]; p = 0.008) hip power production increased
during stair climbing, while nonsurgical ankle absolute
(preoperative: 0.9 ± 0.5 [CI, 0.6 - 1.2], 1 year
postoperative: 0.6 ± 0.3 [CI, 0.4-0.8]; p = 0.064) and
normalized (preoperative: 0.13 ± 0.06 [CI, 0.10-0.16], 1
year postoperative: 0.08 ± 0.04 [CI, 0.06-0.10]; p = 0.015)
power decreased during stair climbing after THA. No
consistent effect of gender was observed.<h4>Conclusions</h4>In
this gait-analysis study, power was improved in hip joints
that were operated on, and power production in the
ipsilateral and contralateral ankles and ipsilateral hips
was reduced during level walking and stair climbing. The
success of surgical intervention must be based on restoring
reasonable balance of forces in the lower limb. Patients
with OA of the hip lose power production in this joint and
must compensate for the loss by producing power in other
joints, which then may become arthritic. To determine future
interventions, an understanding of whether changes in forces
or joint angle affect the change in joint power is needed.
Based on these results, THA appeared to effectively increase
hip power and reduce the need for compensatory power
production in other joints for both men and women in this
patient cohort.<h4>Level of evidence</h4>Level I, prognostic
study.},
Doi = {10.1097/corr.0000000000000809},
Key = {fds345670}
}
@article{fds342136,
Author = {Granatosky, MC and Schmitt, D},
Title = {The mechanical origins of arm-swinging.},
Journal = {Journal of human evolution},
Volume = {130},
Pages = {61-71},
Year = {2019},
Month = {May},
Abstract = {Arm-swinging is a locomotor mode observed only in primates,
in which the hindlimbs no longer have a weight bearing
function and the forelimbs must propel the body forward and
support the entirety of the animal's mass. It has been
suggested that the evolution of arm-swinging was preceded by
a shift to inverted quadrupedal walking for purposes of
feeding and balance, yet little is known about the mechanics
of limb use during inverted quadrupedal walking. In this
study, we test whether the mechanics of inverted quadrupedal
walking make sense as precursors to arm-swinging and whether
there are fundamental differences in inverted quadrupedal
walking in primates compared to non-primate mammals that
would explain the evolution of arm-swinging in primates
only. Based on kinetic limb-loading data collected during
inverted quadrupedal walking in primates (seven species) and
non-primate mammals (three species), we observe that in
primates the forelimb serves as the primary propulsive and
weight bearing limb. Additionally, heavier individuals tend
to support a greater distribution of body weight on their
forelimbs than lighter ones. These kinetic patterns are not
observed in non-primate mammals. Based on these findings, we
propose that the ability to adopt arm-swinging is fairly
simple for relatively large-bodied primates and merely
requires the animal to release its grasping foot from the
substrate. This study fills an important gap concerning the
origins of arm-swinging and illuminates previously unknown
patterns of primate locomotor evolution.},
Doi = {10.1016/j.jhevol.2019.02.001},
Key = {fds342136}
}
@article{fds341872,
Author = {Miller, CE and Johnson, LE and Pinkard, H and Lemelin, P and Schmitt,
D},
Title = {Limb phase flexibility in walking: A test case in the
squirrel monkey (Saimiri sciureus)},
Journal = {Frontiers in Zoology},
Volume = {16},
Number = {1},
Year = {2019},
Month = {February},
Abstract = {Background: Previous analyses of factors influencing
footfall timings and gait selection in quadrupeds have
focused on the implications for energetic cost or gait
mechanics separately. Here we present a model for
symmetrical walking gaits in quadrupedal mammals that
combines both factors, and aims to predict the substrate
contexts in which animals will select certain ranges of
footfall timings that (1) minimize energetic cost, (2)
minimize rolling and pitching moments, or (3) balance the
two. We hypothesize that energy recovery will be a priority
on all surfaces, and will be the dominant factor determining
footfall timings on flat, ground-like surfaces. The ability
to resist pitch and roll, however, will play a larger role
in determining footfall choice on narrower and more complex
branch-like substrates. As a preliminary test of the
expectations of the model, we collected sample data on
footfall timings in a primate with relatively high
flexibility in footfall timings-the squirrel monkey (Saimiri
sciureus)-walking on a flat surface, straight pole, and a
pole with laterally-projecting branches to simulate
simplified ground and branch substrates. We compare limb
phase values on these supports to the expectations of the
model. Results: As predicted, walking steps on the flat
surface tended towards limb phase values that promote energy
exchange. Both pole substrates induced limb phase values
predicted to favor reduced pitching and rolling moments.
Conclusions: These data provide novel insight into the ways
in which animals may choose to adjust their behavior in
response to movement on flat versus complex substrates and
the competing selective factors that influence footfall
timing in mammals. These data further suggest a pathway for
future investigations using this perspective.},
Doi = {10.1186/s12983-019-0299-8},
Key = {fds341872}
}
@article{fds341494,
Author = {Miller, CE and Pinkard, H and Johnson, LE and Schmitt,
D},
Title = {Pitch control and speed limitation during overground
deceleration in lemurid primates.},
Journal = {Journal of morphology},
Volume = {280},
Number = {2},
Pages = {300-306},
Year = {2019},
Month = {February},
Abstract = {An animal's fitness is influenced by the ability to move
safely through its environment. Recent models have shown
that aspects of body geometry, for example, limb length and
center of mass (COM) position, appear to set limits for
pitch control in cursorial quadrupeds. Models of pitch
control predict that the body shape of these and certain
other primates, with short forelimbs and posteriorly
positioned COM, should allow them to decelerate rapidly
while minimizing the risk of pitching forward. We chose to
test these models in two non-cursorial lemurs: Lemur catta,
the highly terrestrial ring-tailed lemur, and Eulemur
fulvus, the highly arboreal brown lemur. We modeled the
effects of changes in limb length and COM position on
maximum decelerative potential for both species, as well as
collecting data on maximal decelerations across whole
strides. In both species, maximum measured decelerations
fell below the range of pitch-limited deceleration values
predicted by the geometric model, with the ring-tailed lemur
approaching its pitch limit more closely. Both lemurs showed
decelerative potential equivalent to or higher than horses,
the only comparative model currently available. These data
reinforce the hypothesis that a relatively simple model of
body geometry can predict aspects of maximum performance in
animals. In this case, it appears that the body geometry of
primates is skewed toward avoiding forward pitch in maximal
decelerations.},
Doi = {10.1002/jmor.20944},
Key = {fds341494}
}
@article{fds341495,
Author = {Granatosky, MC and Schmitt, D and Hanna, J},
Title = {Comparison of spatiotemporal gait characteristics between
vertical climbing and horizontal walking in
primates.},
Journal = {The Journal of experimental biology},
Volume = {222},
Number = {Pt 2},
Pages = {jeb185702},
Year = {2019},
Month = {January},
Abstract = {During quadrupedal walking, most primates utilize
diagonal-sequence diagonal-couplet gaits, large limb
excursions and hindlimb-biased limb loading. These gait
characteristics are thought to be basal to primates, but the
selective pressure underlying these gait changes remains
unknown. Some researchers have examined these
characteristics during vertical climbing and propose that
primate quadrupedal gait characteristics may have arisen due
to the mechanical challenges of moving on vertical supports.
Unfortunately, these studies are usually limited in scope
and do not account for varying strategies based on body size
or phylogeny. Here, we test the hypothesis that the
spatiotemporal gait characteristics that are used during
horizontal walking in primates are also present during
vertical climbing irrespective of body size and phylogeny.
We examined footfall patterns, diagonality, speed and stride
length in eight species of primates across a range of body
masses. We found that, during vertical climbing, primates
slow down, keep more limbs in contact with the substrate at
any one time, and increase the frequency of lateral-sequence
gaits compared with horizontal walking. Taken together,
these characteristics are assumed to increase stability
during locomotion. Phylogenetic relatedness and body size
differences have little influence on locomotor patterns
observed across species. These data reject the idea that the
suite of spatiotemporal gait features observed in primates
during horizontal walking are in some way evolutionarily
linked to selective pressures associated with mechanical
requirements of vertical climbing. These results also
highlight the importance of behavioral flexibility for
negotiating the challenges of locomotion in an arboreal
environment.},
Doi = {10.1242/jeb.185702},
Key = {fds341495}
}
@article{fds338039,
Author = {Fabre, A-C and Granatosky, MC and Hanna, JB and Schmitt,
D},
Title = {Do forelimb shape and peak forces co-vary in
strepsirrhines?},
Journal = {American journal of physical anthropology},
Volume = {167},
Number = {3},
Pages = {602-614},
Year = {2018},
Month = {November},
Abstract = {<h4>Objectives</h4>In this study, we explore whether ground
reaction forces recorded during horizontal walking co-vary
with the shape of the long bones of the forelimb in
strepsirrhines. To do so, we quantify (1) the shape of the
shaft and articular surfaces of each long bone of the
forelimb, (2) the peak vertical, mediolateral, and
horizontal ground reaction forces applied by the forelimb
during arboreal locomotion, and (3) the relationship between
the shape of the forelimb and peak forces.<h4>Materials and
methods</h4>Geometric morphometric approaches were used to
quantify the shape of the bones. Kinetic data were collected
during horizontal arboreal walking in eight species of
strepsirrhines that show variation in habitual substrate use
and morphology of the forelimb. These data were then used to
explore the links between locomotor behavior, morphology,
and mechanics using co-variation analyses in a phylogenetic
framework.<h4>Results</h4>Our results show significant
differences between slow quadrupedal climbers (lorises),
vertical clinger and leapers (sifaka), and active arboreal
quadrupeds (ring-tailed lemur, ruffed lemur) in both ground
reaction forces and the shape of the long bones of the
forelimb, with the propulsive and medially directed peak
forces having the highest impact on the shape of the
humerus. Co-variation between long bone shape and ground
reaction forces was detected in both the humerus and ulna
even when accounting for differences in body
mass.<h4>Discussion</h4>These results demonstrate the
importance of considering limb-loading beyond just peak
vertical force, or substrate reaction force. A re-evaluation
of osseous morphology and functional interpretations is
necessary in light of these findings.},
Doi = {10.1002/ajpa.23688},
Key = {fds338039}
}
@article{fds337047,
Author = {Snyder, ML and Schmitt, D},
Title = {Effects of aging on the biomechanics of Coquerel's sifaka
(Propithecus coquereli): Evidence of robustness to
senescence.},
Journal = {Experimental gerontology},
Volume = {111},
Pages = {235-240},
Publisher = {Elsevier BV},
Year = {2018},
Month = {October},
Abstract = {It is well-known that as humans age they experience
significant changes in gait including reduction in velocity
and ground reaction forces and changes in leg mechanics.
Progressive changes in gait can lead to disability and
frailty, defined as an inability to carry out activities of
daily living. This topic is relevant to basic understanding
of the aging process and for clinical intervention. As such,
studies of frailty can benefit from nonhuman animal models,
yet little is known about gait frailty in nonhuman primates.
This study examines a nonhuman primate model to evaluate its
relevance to understanding human aging processes. To test
the null hypothesis that age-related changes in joint
function and gait do occur in primate models in a similar
fashion to humans, a detailed gait analysis, including
velocity, footfall timings, and vertical ground reaction
forces, on bipedal locomotion was performed in Coquerel's
sifaka (Propithecus coquereli), ranging in age from
5 years to 24 years. None of the spatiotemporal or
kinetic gait variables measured was significantly correlated
with age alone. There was a slight but significant reduction
in locomotor velocity when animals were grouped into "young"
and "old" categories. These data show that aging P.
coquereli experience only subtle age-related changes, that
were not nearly as extensive as reported in humans. This
lack of change suggests that unlike humans, lemurs maintain
gait competency at high levels, possibly because these
animals maintain reproductive capacity close to their age of
death and that frailty may be selected against, since gait
disability would result in injury and death that would
preclude independent living. Although nonhuman primates
should experience age-related senescence, their locomotor
performance should remain robust throughout their lifetimes,
which raises questions about the use of primate models of
gait disability, an area that deserves further
investigation.},
Doi = {10.1016/j.exger.2018.07.019},
Key = {fds337047}
}
@article{fds337048,
Author = {Hughes-Oliver, CN and Srinivasan, D and Schmitt, D and Queen,
RM},
Title = {Gender and limb differences in temporal gait parameters and
gait variability in ankle osteoarthritis.},
Journal = {Gait & posture},
Volume = {65},
Pages = {228-233},
Year = {2018},
Month = {September},
Abstract = {BACKGROUND:The effects of ankle osteoarthritis on gait are
noticeable in the clinic, but are difficult to quantify and
score without detailed kinematic and kinetic analysis.
Evaluationof temporal gait parameters and gait variability
is a potential alternative. RESEARCH QUESTION:This study
aimed to determine associations between limb and gender with
temporal gait parameters and gait variability in ankle OA
patients to evaluate the utility of these parameters for
gait assessment in a clinical setting. METHODS:Following
informed consent, 242 end-stage unilateral ankle OA patients
walked at self-selected speed across force plates. Means and
stride-to-stride standard deviations (SD) of stride, swing,
stance, and double support times were determined for each
patient. Limb x Gender ANCOVA models co-varying for walking
speed were run for swing and stance times, while stride and
double support times were only compared between genders.
Statistical analysis was performed in SPSS (α = 0.05).
RESULTS:Walking speed affected all measures of interest.
After adjusting for walking speed, mean stride time, stride
time SD, and stance time SD were 3.5%, 67% and 29% higher
among women than men (p = 0.002, 0.035 and 0.02
respectively). Swing time was 12% higher and stance time was
6% lower on the affected side compared to the unaffected
side (p < 0.001 for both). SIGNIFICANCE:Women have
longer stride times and higher variability, which may
indicate higher fall risk. Both genders minimized loading on
the affected limb by increasing swing time and reducing
stance time on the affected side. Simple, easy to record
temporal gait patterns can provide useful insight into gait
abnormalities in patients with ankle OA.},
Doi = {10.1016/j.gaitpost.2018.07.180},
Key = {fds337048}
}
@article{fds329281,
Author = {Zeininger, A and Schmitt, D and Jensen, JL and Shapiro,
LJ},
Title = {Ontogenetic changes in foot strike pattern and calcaneal
loading during walking in young children.},
Journal = {Gait & posture},
Volume = {59},
Pages = {18-22},
Year = {2018},
Month = {January},
Abstract = {The assumption that the morphology of the human calcaneus
reflects high and cyclical impact forces at heel strike
during adult human walking has never been experimentally
tested. Since a walking step with a heel strike is an
emergent behavior in children, an ontogenetic study provides
a natural experiment to begin testing the relationship
between the mechanics of heel strike and calcaneal anatomy.
This study examined the ground reaction forces (GRFs) of
stepping in children to determine the location of the center
of pressure (COP) relative to the calcaneus and the
orientation and magnitude of ground reaction forces during
foot contact. Three-dimensional kinematic and kinetic data
were analyzed for 18 children ranging in age from 11.5 to
43.1 months. Early steppers used a flat foot contact (FFC)
and experienced relatively high vertical and resultant GRFs
with COP often anterior to the calcaneus. More experienced
walkers used an initial heel contact (IHC) in which GRFs
were significantly lower but the center of pressure remained
under the heel a greater proportion of time. Thus, during
FFC the foot experienced higher loading, but the heel itself
was relatively wider and the load was distributed more
evenly. In IHC walkers load was concentrated on the anterior
calcaneus and a narrower heel, suggesting a need for
increased calcaneal robusticity during development to
mitigate injury. These results provide new insight into foot
loading outside of typical mature contact patterns, inform
structure-function relationships during development, and
illuminate potential causes of heel injury in young
walkers.},
Doi = {10.1016/j.gaitpost.2017.09.027},
Key = {fds329281}
}
@article{fds332803,
Author = {Granatosky, MC and Fitzsimons, A and Zeininger, A and Schmitt,
D},
Title = {Mechanisms for the functional differentiation of the
propulsive and braking roles of the forelimbs and hindlimbs
during quadrupedal walking in primates and
felines.},
Journal = {The Journal of experimental biology},
Volume = {221},
Number = {Pt 2},
Pages = {jeb162917},
Year = {2018},
Month = {January},
Abstract = {During quadrupedal walking in most animals, the forelimbs
play a net braking role, whereas the hindlimbs are net
propulsive. However, the mechanism by which this
differentiation occurs remains unclear. Here, we test two
models to explain this pattern using primates and felines:
(1) the horizontal strut effect (in which limbs are modeled
as independent struts), and (2) the linked strut model (in
which limbs are modeled as linked struts with a center of
mass in between). Video recordings were used to determine
point of contact, timing of mid-stance, and limb
protraction/retraction duration. Single-limb forces were
used to calculate contact time, impulses and the proportion
of the stride at which the braking-to-propulsive transition
(BP) occurred for each limb. We found no association between
the occurrence of the BP and mid-stance, little influence of
protraction and retraction duration on the
braking-propulsive function of a limb, and a causative
relationship between vertical force distribution between
limbs and the patterns of horizontal forces. These findings
reject the horizontal strut effect, and provide some support
for the linked strut model, although predictions were not
perfectly matched. We suggest that the position of the
center of mass relative to limb contact points is a very
important, but not the only, factor driving functional
differentiation of the braking and propulsive roles of the
limbs in quadrupeds. It was also found that primates have
greater differences in horizontal impulse between their
limbs compared with felines, a pattern that may reflect a
fundamental arboreal adaptation in primates.},
Doi = {10.1242/jeb.162917},
Key = {fds332803}
}
@article{fds329280,
Author = {Queen, RM and Franck, CT and Schmitt, D and Adams,
SB},
Title = {Are There Differences in Gait Mechanics in Patients With A
Fixed Versus Mobile Bearing Total Ankle Arthroplasty? A
Randomized Trial.},
Journal = {Clin Orthop Relat Res},
Volume = {475},
Number = {10},
Pages = {2599-2606},
Year = {2017},
Month = {October},
Abstract = {BACKGROUND: Total ankle arthroplasty (TAA) is an alternative
to arthrodesis, but no randomized trial has examined whether
a fixed bearing or mobile bearing implant provides improved
gait mechanics. QUESTIONS/PURPOSES: We wished to determine
if fixed- or mobile-bearing TAA results in a larger
improvement in pain scores and gait mechanics from before
surgery to 1 year after surgery, and to quantify
differences in outcomes using statistical analysis and
report the standardized effect sizes for such comparisons.
METHODS: Patients with end-stage ankle arthritis who were
scheduled for TAA between November 2011 and June 2013
(n = 40; 16 men, 24 women; average age, 63 years; age
range, 35-81 years) were prospectively recruited for this
study from a single foot and ankle orthopaedic clinic.
During this period, 185 patients underwent TAA, with 144
being eligible to participate in this study. Patients were
eligible to participate if they were able to meet all study
inclusion criteria, which were: no previous diagnosis of
rheumatoid arthritis, a contralateral TAA, bilateral ankle
arthritis, previous revision TAA, an ankle fusion revision,
or able to walk without the use of an assistive device,
weight less than 250 pounds (114 kg), a sagittal or coronal
plane deformity less than 15°, no presence of avascular
necrosis of the distal tibia, no current neuropathy, age
older than 35 years, no history of a talar neck fracture,
or an avascular talus. Of the 144 eligible patients, 40
consented to participate in our randomized trial. These 40
patients were randomly assigned to either the fixed
(n = 20) or mobile bearing implant group (n = 20).
Walking speed, bilateral peak dorsiflexion angle, peak
plantar flexion angle, sagittal plane ankle ROM, peak ankle
inversion angle, peak plantar flexion moment, peak plantar
flexion power during stance, peak weight acceptance, and
propulsive vertical ground reaction force were analyzed
during seven self-selected speed level walking trials for 33
participants using an eight-camera motion analysis system
and four force plates. Seven patients were not included in
the analysis owing to cancelled surgery (one from each
group) and five were lost to followup (four with fixed
bearing and one with mobile bearing implants). A series of
effect-size calculations and two-sample t-tests comparing
postoperative and preoperative increases in outcome
variables between implant types were used to determine the
differences in the magnitude of improvement between the two
patient cohorts from before surgery to 1 year after
surgery. The sample size in this study enabled us to detect
a standardized shift of 1.01 SDs between group means with
80% power and a type I error rate of 5% for all outcome
variables in the study. RESULTS: This randomized trial did
not reveal any differences in outcomes between the two
implant types under study at the sample size collected. In
addition to these results, effect size analysis suggests
that changes in outcome differ between implant types by less
than 1 SD. Detection of the largest change score or observed
effect (propulsive vertical ground reaction force [Fixed:
0.1 ± 0.1; 0.0-1.0; Mobile: 0.0 ± 0.1; 0.0-0.0;
p = 0.0.051]) in this study would require a future trial
to enroll 66 patients. However, the smallest change score or
observed effect (walking speed [Fixed: 0.2 ± 0.3;
0.1-0.4; Mobile: 0.2 ± 0.3; 0.0-0.3; p = 0.742])
requires a sample size of 2336 to detect a significant
difference with 80% power at the observed effect sizes.
CONCLUSIONS: To our knowledge, this is the first randomized
study to report the observed effect size comparing
improvements in outcome measures between fixed and mobile
bearing implant types. This study was statistically powered
to detect large effects and descriptively analyze observed
effect sizes. Based on our results there were no
statistically or clinically meaningful differences between
the fixed and mobile bearing implants when examining gait
mechanics and pain 1 year after TAA. LEVEL OF EVIDENCE:
Level II, therapeutic study.},
Doi = {10.1007/s11999-017-5405-7},
Key = {fds329280}
}
@article{fds328892,
Author = {Hanna, JB and Granatosky, MC and Rana, P and Schmitt,
D},
Title = {The evolution of vertical climbing in primates: evidence
from reaction forces.},
Journal = {The Journal of experimental biology},
Volume = {220},
Number = {Pt 17},
Pages = {3039-3052},
Year = {2017},
Month = {September},
Abstract = {Vertical climbing is an essential behavior for arboreal
animals, yet limb mechanics during climbing are poorly
understood and rarely compared with those observed during
horizontal walking. Primates commonly engage in both
arboreal walking and vertical climbing, and this makes them
an ideal taxa in which to compare these locomotor forms.
Additionally, primates exhibit unusual limb mechanics
compared with most other quadrupeds, with weight
distribution biased towards the hindlimbs, a pattern that is
argued to have evolved in response to the challenges of
arboreal walking. Here we test an alternative hypothesis
that functional differentiation between the limbs evolved
initially as a response to climbing. Eight primate species
were recorded locomoting on instrumented vertical and
horizontal simulated arboreal runways. Forces along the axis
of, and normal to, the support were recorded. During
walking, all primates displayed forelimbs that were net
braking, and hindlimbs that were net propulsive. In
contrast, both limbs served a propulsive role during
climbing. In all species, except the lorisids, the hindlimbs
produced greater propulsive forces than the forelimbs during
climbing. During climbing, the hindlimbs tends to support
compressive loads, while the forelimb forces tend to be
primarily tensile. This functional disparity appears to be
body-size dependent. The tensile loading of the forelimbs
versus the compressive loading of the hindlimbs observed
during climbing may have important evolutionary implications
for primates, and it may be the case that hindlimb-biased
weight support exhibited during quadrupedal walking in
primates may be derived from their basal condition of
climbing thin branches.},
Doi = {10.1242/jeb.157628},
Key = {fds328892}
}
@article{fds328893,
Author = {Granatosky, MC and Schmitt, D},
Title = {Forelimb and hind limb loading patterns during below branch
quadrupedal locomotion in the two-toed sloth},
Journal = {Journal of Zoology},
Volume = {302},
Number = {4},
Pages = {271-278},
Publisher = {WILEY},
Year = {2017},
Month = {August},
Abstract = {The living sloths are the most suspensory of all extant
mammals, and therefore represent ideal models for
investigating the effects that suspensory behaviours have on
bone and joint morphology. While the anatomy and kinematics
of sloths are well known, no research has reported kinetic
patterns of sloth locomotion. This study examines peak force
patterns generated by the two-toed sloth Choloepus
didactylus during below branch quadrupedal walking to infer
how kinetic patterns of sloths compare to data reported on
non-human primates. Values for vertical, fore-aft, and
mediolateral peak forces were collected for the forelimb and
hind limb, and analyses between the magnitude and timing of
these peaks were compared between forelimbs and hind limbs.
Patterns and timing of fore-aft peak forces were similar
between sloths and non-human primates, and were
characterized by first a propulsive force as the limb first
made contact with the support followed by braking force
prior to lift-off. Similarly, both sloths and primates
demonstrate a medially directed force bias onto the
substrate during below branch quadrupedal locomotion,
although the magnitude observed in sloths exceeds values
reported in primates. Peak vertical forces applied by the
forelimbs and hind limbs of sloths were not statistically
different in magnitude from each other. Data from this study
indicate the forelimbs and hind limbs of sloths are
functioning similarly to each other during below branch
quadrupedal locomotion, and that forelimb-biased weight
support, the pattern typical of primates, is not a
mechanical requirement of suspensory locomotion across all
mammals. These findings provide important information about
the mechanical necessities of below branch movement, and
data from this study should be used when considering
mechanical convergence among suspensory taxa and the
interpretation of suspensory limb adaptations in the fossil
record.},
Doi = {10.1111/jzo.12455},
Key = {fds328893}
}
@article{fds327238,
Author = {Fabre, A-C and Marigó, J and Granatosky, MC and Schmitt,
D},
Title = {Functional associations between support use and forelimb
shape in strepsirrhines and their relevance to inferring
locomotor behavior in early primates.},
Journal = {Journal of human evolution},
Volume = {108},
Pages = {11-30},
Year = {2017},
Month = {July},
Abstract = {The evolution of primates is intimately linked to their
initial invasion of an arboreal environment. However, moving
and foraging in this milieu creates significant mechanical
challenges related to the presence of substrates differing
in their size and orientation. It is widely assumed that
primates are behaviorally and anatomically adapted to
movement on specific substrates, but few explicit tests of
this relationship in an evolutionary context have been
conducted. Without direct tests of form-function
relationships in living primates it is impossible to
reliably infer behavior in fossil taxa. In this study, we
test a hypothesis of co-variation between forelimb
morphology and the type of substrates used by
strepsirrhines. If associations between anatomy and
substrate use exist, these can then be applied to better
understand limb anatomy of extinct primates. The
co-variation between each forelimb long bone and the type of
substrate used was studied in a phylogenetic context. Our
results show that despite the presence of significant
phylogenetic signal for each long bone of the forelimb,
clear support use associations are present. A strong
co-variation was found between the type of substrate used
and the shape of the radius, with and without taking
phylogeny into account, whereas co-variation was significant
for the ulna only when taking phylogeny into account.
Species that use a thin branch milieu show radii that are
gracile and straight and have a distal articular shape that
allows for a wide range of movements. In contrast, extant
species that commonly use large supports show a relatively
robust and curved radius with an increased surface area
available for forearm and hand muscles in pronated posture.
These results, especially for the radius, support the idea
that strepsirrhine primates exhibit specific skeletal
adaptations associated with the supports that they
habitually move on. With these robust associations in hand
it will be possible to explore the same variables in extinct
early primates and primate relatives and thus improve the
reliability of inferences concerning substrate use in early
primates.},
Doi = {10.1016/j.jhevol.2017.03.012},
Key = {fds327238}
}
@article{fds325684,
Author = {Gruss, LT and Gruss, R and Schmitt, D},
Title = {Pelvic Breadth and Locomotor Kinematics in Human
Evolution.},
Journal = {Anatomical record (Hoboken, N.J. : 2007)},
Volume = {300},
Number = {4},
Pages = {739-751},
Editor = {Rosenberg, KR and Desilva, JM},
Year = {2017},
Month = {April},
Abstract = {A broad pelvis is characteristic of most, if not all,
pre-modern hominins. In at least some early
australopithecines, most notably the female Australopithecus
afarensis specimen known as "Lucy," it is very broad and
coupled with very short lower limbs. In 1991, Rak suggested
that Lucy's pelvic anatomy improved locomotor efficiency by
increasing stride length through rotation of the wide pelvis
in the axial plane. Compared to lengthening strides by
increasing flexion and extension at the hips, this mechanism
could avoid potentially costly excessive vertical
oscillations of the body's center of mass (COM). Here, we
test this hypothesis. We examined 3D kinematics of walking
at various speeds in 26 adult subjects to address the
following questions: Do individuals with wider pelves take
longer strides, and do they use a smaller degree of hip
flexion and extension? Is pelvic rotation greater in
individuals with shorter legs, and those with narrower
pelves? Our results support Rak's hypothesis. Subjects with
wider pelves do take longer strides for a given velocity,
and for a given stride length they flex and extend their
hips less, suggesting a smoother pathway of the COM.
Individuals with shorter legs do use more pelvic rotation
when walking, but pelvic breadth was not related to pelvic
rotation. These results suggest that a broad pelvis could
benefit any bipedal hominin, but especially a short-legged
australopithecine such as Lucy, by improving locomotor
efficiency, particularly when carrying an infant or
traveling in a foraging group with individuals of varying
sizes. Anat Rec, 300:739-751, 2017. © 2017 Wiley
Periodicals, Inc.},
Doi = {10.1002/ar.23550},
Key = {fds325684}
}
@article{fds322453,
Author = {Larsen, RJ and Jackson, WH and Schmitt, D},
Title = {Mechanisms for regulating step length while running towards
and over an obstacle.},
Journal = {Human movement science},
Volume = {49},
Pages = {186-195},
Year = {2016},
Month = {October},
Abstract = {The ability to run across uneven terrain with continuous
stable movement is critical to the safety and efficiency of
a runner. Successful step-to-step stabilization while
running may be mediated by minor adjustments to a few key
parameters (e.g., leg stiffness, step length, foot strike
pattern). However, it is not known to what degree runners in
relatively natural settings (e.g., trails, paved road,
curbs) use the same strategies across multiple steps. This
study investigates how three readily measurable running
parameters - step length, foot placement, and foot strike
pattern - are adjusted in response to encountering a typical
urban obstacle - a sidewalk curb. Thirteen subjects were
video-recorded as they ran at self-selected slow and fast
paces. Runners targeted a specific distance before the curb
for foot placement, and lengthened their step over the curb
(p<0.0001) regardless of where the step over the curb was
initiated. These strategies of adaptive locomotion disrupt
step cycles temporarily, and may increase locomotor cost and
muscle loading, but in the end assure dynamic stability and
minimize the risk of injury over the duration of a
run.},
Doi = {10.1016/j.humov.2016.07.002},
Key = {fds322453}
}
@article{fds329921,
Author = {Burgess, ML and Schmitt, D and Zeininger, A and McFarlin, SC and Zihlman, AL and Polk, JD and Ruff, CB},
Title = {Ontogenetic scaling of fore limb and hind limb joint posture
and limb bone cross-sectional geometry in vervets and
baboons.},
Journal = {American journal of physical anthropology},
Volume = {161},
Number = {1},
Pages = {72-83},
Year = {2016},
Month = {September},
Abstract = {<h4>Objectives</h4>Previous studies suggest that the
postures habitually adopted by an animal influence the
mechanical loading of its long bones. Relatively extended
limb postures in larger animals should preferentially reduce
anteroposterior (A-P) relative to mediolateral (M-L) bending
of the limb bones and therefore decrease A-P/M-L rigidity.
We test this hypothesis by examining growth-related changes
in limb bone structure in two primate taxa that differ in
ontogenetic patterns of joint posture.<h4>Materials and
methods</h4>Knee and elbow angles of adult and immature
vervets (Chlorocebus aethiops, n = 16) were compared to
published data for baboons (Papio hamadryas ursinus,
n = 33, Patel et al., ). Ontogenetic changes in ratios
of A-P/M-L bending rigidity in the femur and humerus were
compared in skeletal samples (C. aethiops, n = 28; P.
cynocephalus, n = 39). Size changes were assessed with
linear regression, and age group differences tested with
ANOVA.<h4>Results</h4>Only the knee of baboons shows
significant postural change, becoming more extended with age
and mass. A-P/M-L bending rigidity of the femur decreases
during ontogeny in immature and adult female baboons only.
Trends in the humerus are less marked. Adult male baboons
have higher A-P/M-L bending rigidity of the femur than
females.<h4>Conclusions</h4>The hypothesized relationship
between more extended joints and reduced A-P/M-L bending
rigidity is supported by our results for immature and adult
female baboon hind limbs, and the lack of significant age
changes in either parameter in forelimbs and vervets. Adult
males of both species depart from general ontogenetic
trends, possibly due to socially mediated behavioral
differences between sexes. Am J Phys Anthropol 161:72-83,
2016. © 2016 Wiley Periodicals, Inc.},
Doi = {10.1002/ajpa.23009},
Key = {fds329921}
}
@article{fds322454,
Author = {Queen, RM and Sparling, TL and Schmitt, D},
Title = {Hip, Knee, and Ankle Osteoarthritis Negatively Affects
Mechanical Energy Exchange.},
Journal = {Clinical orthopaedics and related research},
Volume = {474},
Number = {9},
Pages = {2055-2063},
Year = {2016},
Month = {September},
Abstract = {<h4>Background</h4>Individuals with osteoarthritis (OA) of
the lower limb find normal locomotion tiring compared with
individuals without OA, possibly because OA of any lower
limb joint changes limb mechanics and may disrupt transfer
of potential and kinetic energy of the center of mass during
walking, resulting in increased locomotor costs. Although
recovery has been explored in asymptomatic individuals and
in some patient populations, the effect of changes in these
gait parameters on center of mass movements and mechanical
work in patients with OA in specific joints has not been
well examined. The results can be used to inform clinical
interventions and rehabilitation that focus on improving
energy recovery.<h4>Questions/purposes</h4>We hypothesized
that (1) individuals with end-stage lower extremity OA would
exhibit a decrease in walking velocity compared with
asymptomatic individuals and that the joint affected with OA
would differntially influence walking velocity, (2)
individuals with end-stage lower extremity OA would show
decreased energy recovery compared with asymptomatic
individuals and that individuals with end-stage hip and
ankle OA would have greater reductions in recovery than
would individuals with end-stage knee OA owing to
restrictions in hip and ankle motion, and (3) that
differences in the amplitude and congruity of the center of
mass would explain the differences in energy recovery that
are observed in each population.<h4>Methods</h4>Ground
reaction forces at a range of self-selected walking speeds
were collected from individuals with end-stage radiographic
hip OA (n = 27; 14 males, 13 females; average age, 55.6
years; range, 41-70 years), knee OA (n = 20; seven males, 13
females; average age, 61.7 years; range, 49-74 years), ankle
OA (n = 30; 14 males, 16 females; average age, 57 years;
range, 45-70 years), and asymptomatic individuals (n = 13;
eight males, five females; average age, 49.8 years; range,
41-67 years). Participants were all patients with end-stage
OA who were scheduled to have joint replacement surgery
within 4 weeks of testing. All patients were identified by
the orthopaedic surgeon as having end-stage radiographic
disease and to be a candidate for joint replacement surgery.
Patients were excluded if they had pain at any other lower
extremity joint, previous joint replacement surgery, or
needed to use an assistive device for ambulation. Patients
were enrolled if they met the study inclusion criteria. Our
study was comparative and cohorts could be compared with
each other, however, the asymptomatic group served to verify
our methods and provided a recovery standard with which we
could compare our patients. Potential and kinetic energy
relationships (% congruity) and energy exchange (% recovery)
were calculated. Linear regressions were used to examine the
effect of congruity and amplitude of energy fluctuations and
walking velocity on % recovery. Analysis of covariance was
used to compare energy recovery between groups.<h4>Results</h4>The
results of this study support our hypothesis that
individuals with OA walk at a slower velocity than
asymptomatic individuals (1.4 ± 0.2 m/second, 1.2-1.5
m/second) and that the joint affected by OA also affects
walking velocity (p < 0.0001). The cohort with ankle OA (0.9
± 0.2 m/second, 0.77-0.94 m/second) walked at a slower
speed relative to the cohort with hip OA (1.1 ± 0.2
m/second, 0.96-1.1 m/second; p = 0.002). However, when
comparing the cohorts with ankle and knee OA (0.9 ± 0.2
m/second, 0.77-0.94 m/second) there was no difference in
walking speed (p = 0.16) and the same was true when
comparing the cohorts with knee and hip OA (p = 0.14).
Differences in energy recovery existed when comparing the OA
cohorts with the asymptomatic cohort and when examining
differences between the OA cohorts. After adjusting for
walking speeds these results showed that asymptomatic
individuals (65% ± 3%, 63%-67%) had greater recovery than
individuals with hip OA (54% ± 10%, 50%-58%; p = 0.014) and
ankle OA (47% ± 13%, 40%-52%; p = 0.002) but were not
different compared with individuals with knee OA (57% ±
10%, 53%-62%; p = 0.762). When speed was accounted for, 80%
of the variation in recovery not attributable to speed was
explained by congruity with only 10% being explained by
amplitude.<h4>Conclusions</h4>OA in the hip, knee, or ankle
reduces effective exchange of potential and kinetic energy,
potentially increasing the muscular work required to control
movements of the center of mass.<h4>Clinical
relevance</h4>The fatigue and limited physical activity
reported in patients with lower extremity OA could be
associated with increased mechanical work of the center of
mass. Focused gait retraining potentially could improve
walking mechanics and decrease fatigue in these
patients.},
Doi = {10.1007/s11999-016-4921-1},
Key = {fds322454}
}
@article{fds322455,
Author = {Granatosky, MC and Tripp, CH and Fabre, A-C and Schmitt,
D},
Title = {Patterns of quadrupedal locomotion in a vertical clinging
and leaping primate (Propithecus coquereli) with
implications for understanding the functional demands of
primate quadrupedal locomotion.},
Journal = {American journal of physical anthropology},
Volume = {160},
Number = {4},
Pages = {644-652},
Year = {2016},
Month = {August},
Abstract = {<h4>Objectives</h4>Many primates exhibit a suite of
characteristics that distinguish their quadrupedal gaits
from non-primate mammals including the use of a diagonal
sequence gait, a relatively protracted humerus at touchdown,
and relatively high peak vertical forces on the hindlimbs
compared to the forelimbs. These characteristics are thought
to have evolved together in early, small-bodied primates
possibly in response to the mechanical demands of navigating
and foraging in a complex arboreal environment. It remains
unclear, however, whether primates that employ
quadrupedalism only rarely demonstrate the common primate
pattern of quadrupedalism or instead use the common
non-primate pattern or an entirely different mechanical
pattern from either group.<h4>Materials and methods</h4>This
study compared the kinematics and kinetics of two habitually
quadrupedal primates (Lemur catta and Varecia variegata) to
those of a dedicated vertical clinger and leaper
(Propithecus coquereli) during bouts of quadrupedal
walking.<h4>Results</h4>All three species employed diagonal
sequence gaits almost exclusively, displayed similar degrees
of humeral protraction, and exhibited lower vertical peak
forces in the forelimbs compared to the hindlimb.<h4>Discussion</h4>From
the data in this study, it is possible to reject the idea
that P. coquereli uses a non-primate pattern of quadrupedal
walking mechanics. Nor do they use an entirely different
mechanical pattern from either most primates or most
non-primates during quadrupedal locomotion. These findings
provide support for the idea that this suite of
characteristics is adaptive for the challenges of arboreal
locomotion in primates and that these features of primate
locomotion may be basal to the order or evolved
independently in multiple lineages including indriids. Am J
Phys Anthropol 160:644-652, 2016. © 2016 Wiley Periodicals,
Inc.},
Doi = {10.1002/ajpa.22991},
Key = {fds322455}
}
@article{fds322456,
Author = {Granatosky, MC and Tripp, CH and Schmitt, D},
Title = {Gait kinetics of above- and below-branch quadrupedal
locomotion in lemurid primates.},
Journal = {The Journal of experimental biology},
Volume = {219},
Number = {Pt 1},
Pages = {53-63},
Year = {2016},
Month = {January},
Abstract = {For primates and other mammals moving on relatively thin
branches, the ability to effectively adopt both above- and
below-branch locomotion is seen as critical for successful
arboreal locomotion, and has been considered an important
step prior to the evolution of specialized suspensory
locomotion within our Order. Yet, little information exists
on the ways in which limb mechanics change when animals
shift from above- to below-branch quadrupedal locomotion.
This study tested the hypothesis that vertical force
magnitude and distribution do not vary between locomotor
modes, but that the propulsive and braking roles of the
forelimb change when animals shift from above- to
below-branch quadrupedal locomotion. We collected kinetic
data on two lemur species (Varecia variegata and Lemur
catta) walking above and below an instrumented arboreal
runway. Values for peak vertical, braking and propulsive
forces as well as horizontal impulses were collected for
each limb. When walking below branch, both species
demonstrated a significant shift in limb kinetics compared
with above-branch movement. The forelimb became both the
primary weight-bearing limb and propulsive organ, while the
hindlimb reduced its weight-bearing role and became the
primary braking limb. This shift in force distribution
represents a shift toward mechanics associated with bimanual
suspensory locomotion, a locomotor mode unusual to primates
and central to human evolution. The ability to make this
change is not accompanied by significant anatomical changes,
and thus likely represents an underlying mechanical
flexibility present in most primates.},
Doi = {10.1242/jeb.120840},
Key = {fds322456}
}
@article{fds290832,
Author = {Johnson, LE and Hanna, J and Schmitt, D},
Title = {Single-limb force data for two lemur species while
vertically clinging.},
Journal = {American journal of physical anthropology},
Volume = {158},
Number = {3},
Pages = {463-474},
Year = {2015},
Month = {November},
ISSN = {0002-9483},
Abstract = {<h4>Objectives</h4>Vertical clinging and climbing have been
integral to hypotheses about primate origins, yet little is
known about how an animal with nails instead of claws
resists gravity while on large, vertical, and cylindrical
substrates. Here we test models of how force is applied to
maintain posture, predicting (1) the shear component force
(Fs ) at the hands will be higher than the feet; (2) the
normal component force (Fn ) at the feet will be relatively
high compared to the hands; (3) the component force
resisting gravity (Fg ) at the feet will be relatively high
compared to the hands; (4) species with a high frequency of
vertical clinging postures will have low Fg at the hands due
to relatively short forelimbs.<h4>Materials and
methods</h4>Using a novel instrumented support, single-limb
force data were collected during clinging postures for the
hands and feet and compared across limbs and species for
Propithecus verreauxi (N = 2), a habitual vertical
clinger and leaper, and Varecia variegata (N = 3), a
habitual above-branch arboreal quadruped.<h4>Results</h4>For
both species, hand Fs were significantly higher than at the
feet and Fn and Fg at the feet were significantly higher
than at the hands. Between species, P. verreauxi has
relatively low Fg at the hands and Fn at the feet than V.
vareigata.<h4>Discussion</h4>These results support previous
models and show that hindlimb loading dominance,
characteristic of primate locomotion, is found during
clinging behaviors and may allow the forelimbs to be used
for foraging while clinging. These findings provide insight
into selective pressures on force distribution in primates
and primate locomotor evolution.},
Doi = {10.1002/ajpa.22803},
Key = {fds290832}
}
@article{fds241056,
Author = {Schmitt, D and Vap, A and Queen, RM},
Title = {Effect of end-stage hip, knee, and ankle osteoarthritis on
walking mechanics.},
Journal = {Gait & posture},
Volume = {42},
Number = {3},
Pages = {373-379},
Year = {2015},
Month = {September},
ISSN = {0966-6362},
Abstract = {This study tested the hypothesis that the presence of
isolated ankle (A-OA; N=30), knee (K-OA; N=20), or hip
(H-OA; N=30) osteoarthritis (OA) compared to asymptomatic
controls (N=15) would lead to mechanical changes in the
affected joint but also in all other lower limb joints and
gait overall. Stride length, stance and swing times, as well
as joint angles and moments at the hip, knee, and ankle were
derived from 3-D kinematic and kinetic data collected from
seven self-selected speed walking trial. Values were
compared across groups using a 1×4 ANCOVA, covarying for
walking speed. With walking speed controlled, the results
indicated a reduction in hip and knee extension and ankle
plantar flexion in accordance with the joint affected. In
addition, OA in one joint had strong effects on other
joints. In both H-OA and K-OA groups the hip never passed
into extension, and A-OA subjects significantly changed hip
kinematics to compensate for lack of plantar flexion.
Finally, OA in any joint led to lower peak vertical forces
as well as extension and plantar flexion moments compared to
controls. The presence of end-stage OA at various lower
extremity joints results in compensatory gait mechanics that
cause movement alterations throughout the lower extremity.
This work reinforces our understanding of the complex
interaction of joints of the lower limb and the importance
of focusing on the mechanics of the entire lower limb when
considering gait disability and potential interventions in
patients with isolated OA.},
Doi = {10.1016/j.gaitpost.2015.07.005},
Key = {fds241056}
}
@article{fds241051,
Author = {Rabey, KN and Li, Y and Norton, JN and Reynolds, RP and Schmitt,
D},
Title = {Vibrating Frequency Thresholds in Mice and Rats:
Implications for the Effects of Vibrations on Animal
Health.},
Journal = {Ann Biomed Eng},
Volume = {43},
Number = {8},
Pages = {1957-1964},
Year = {2015},
Month = {August},
ISSN = {0090-6964},
Abstract = {Vibrations in research facilities can cause complex animal
behavioral and physiological responses that can affect
animal health and research outcomes. The goal of this study
was to determine the range of frequency values, where
animals are unable to attenuate vibrations, and therefore
may be most susceptible to their effects. Anesthetized and
euthanized adult rats and mice were exposed to vibration
frequencies over a wide range (0-600 Hz) and at a constant
magnitude of 0.3 m/s(2). Euthanized animals were
additionally exposed to vibrations at an acceleration of 1
m/s(2). The data showed that at most frequencies rodents
were able to attenuate vibration magnitudes, with values for
the back-mounted accelerometer being substantially less than
that of the table. At frequencies of 41-60 Hz mice did not
attenuate vibration magnitude, but instead the magnitude of
the table and animal were equal or amplified. Rats
experienced the same pattern of non-attenuation between 31
and 50 Hz. Once euthanized, the mice vibrated at a slightly
more elevated frequency (up to 100 Hz). Based on these
results, it may be prudent that in laboratory settings,
vibrations in the ranges reported here should be accounted
for as possible contributors to animal stress and/or
biomechanical changes.},
Doi = {10.1007/s10439-014-1226-y},
Key = {fds241051}
}
@article{fds241054,
Author = {Hanna, JB and Schmitt, D and Wright, K and Eshchar, Y and Visalberghi,
E and Fragaszy, D},
Title = {Kinetics of bipedal locomotion during load carrying in
capuchin monkeys.},
Journal = {Journal of human evolution},
Volume = {85},
Pages = {149-156},
Publisher = {Elsevier BV},
Year = {2015},
Month = {August},
ISSN = {0047-2484},
Abstract = {Facultative bipedalism during load transport in nonhuman
primates has been argued to be an important behavior
potentially leading to the evolution of obligate, extended
limb bipedalism. Understanding the biomechanics of such
behavior may lead to insights about associated morphology,
which may translate to interpretation of features in the
fossil record. Some populations of bearded capuchin monkeys
(Sapajus libidinosus) spontaneously carry heavy loads
bipedally during foraging activities. This study provides
the first data on all three components of ground reaction
force for spontaneous bipedalism during load carriage in a
nonhuman primate. Five individual S. libidinosus (mean body
mass = 2.4 kg ± 0.96) were videorecorded during
bipedalism while carrying a stone (0.93 kg) under natural
conditions. A force plate was embedded in the path of the
monkeys. Spatiotemporal and force data for all three
components of the ground reaction force were recorded for 28
steps. Capuchins exhibited a mean vertical peak force per
total weight (Vpk) for the hindlimb of 1.19 (sd = 0.13),
consistent with those of unloaded capuchins in the
laboratory and for other bipedal primates, including humans.
Vertical force records suggest that capuchins, along with
most nonhuman primates, maintain a relatively compliant leg
during both unloaded and loaded locomotion. Like all other
primates, loaded capuchins maintained laterally (outward)
directed medio-lateral forces, presumably to stabilize
side-to-side movements of the center of mass. Medio-lateral
forces suggest that at near-running speeds dynamic stability
diminishes the need to generate high lateral forces.
Vertical force traces exhibited a measurable impact spike at
foot contact in 85% of the steps recorded. An impact spike
is common in human walking and running but has not been
reported in other bipedal primates. This spike in humans is
thought to lead to bone and cartilage damage. The earliest
biped may have experienced similar impact spikes during
bipedal locomotion, requiring compensatory behaviors or
anatomical features.},
Doi = {10.1016/j.jhevol.2015.05.006},
Key = {fds241054}
}
@article{fds241057,
Author = {Li, Y and Rabey, KN and Schmitt, D and Norton, JN and Reynolds,
RP},
Title = {Characteristics of Vibration that Alter Cardiovascular
Parameters in Mice.},
Journal = {J Am Assoc Lab Anim Sci},
Volume = {54},
Number = {4},
Pages = {372-377},
Year = {2015},
Month = {July},
ISSN = {1559-6109},
Abstract = {We hypothesized that short-term exposure of mice to
vibration within a frequency range thought to be near the
resonant frequency range of mouse tissue and at an
acceleration of 0 to 1 m/s(2) would alter heart rate (HR)
and mean arterial pressure (MAP). We used radiotelemetry to
evaluate the cardiovascular response to vibration in C57BL/6
and CD1 male mice exposed to vertical vibration of various
frequencies and accelerations. MAP was consistently
increased above baseline values at an acceleration near 1
m/s(2) and a frequency of 90 Hz in both strains, and HR was
increased also in C57BL/6 mice. In addition, MAP increased
at 80 Hz in individual mice of both strains. When both
strains were analyzed together, mean MAP and HR were
increased at 90 Hz at 1 m/s(2), and HR was increased at 80
Hz at 1 m/s(2). No consistent change in MAP or HR occurred
when mice were exposed to frequencies below 80 Hz or above
90 Hz. The increase in MAP and HR occurred only when the
mice had conscious awareness of the vibration, given that
these changes did not occur when anesthetized mice were
exposed to vibration. Tested vibration acceleration levels
lower than 0.75 m/s(2) did not increase MAP or HR at 80 or
90 Hz, suggesting that a relatively high level of vibration
is necessary to increase these parameters. These data are
important to establish the harmful frequencies and
accelerations of environmental vibration that should be
minimized or avoided in mouse facilities.},
Key = {fds241057}
}
@article{fds241055,
Author = {Gruss, LT and Schmitt, D},
Title = {The evolution of the human pelvis: changing adaptations to
bipedalism, obstetrics and thermoregulation.},
Journal = {Philosophical transactions of the Royal Society of London.
Series B, Biological sciences},
Volume = {370},
Number = {1663},
Pages = {20140063},
Year = {2015},
Month = {March},
ISSN = {0962-8436},
Abstract = {The fossil record of the human pelvis reveals the selective
priorities acting on hominin anatomy at different points in
our evolutionary history, during which mechanical
requirements for locomotion, childbirth and thermoregulation
often conflicted. In our earliest upright ancestors,
fundamental alterations of the pelvis compared with
non-human primates facilitated bipedal walking. Further
changes early in hominin evolution produced a platypelloid
birth canal in a pelvis that was wide overall, with flaring
ilia. This pelvic form was maintained over 3-4 Myr with only
moderate changes in response to greater habitat diversity,
changes in locomotor behaviour and increases in brain size.
It was not until Homo sapiens evolved in Africa and the
Middle East 200 000 years ago that the narrow anatomically
modern pelvis with a more circular birth canal emerged. This
major change appears to reflect selective pressures for
further increases in neonatal brain size and for a narrow
body shape associated with heat dissipation in warm
environments. The advent of the modern birth canal, the
shape and alignment of which require fetal rotation during
birth, allowed the earliest members of our species to deal
obstetrically with increases in encephalization while
maintaining a narrow body to meet thermoregulatory demands
and enhance locomotor performance.},
Doi = {10.1098/rstb.2014.0063},
Key = {fds241055}
}
@article{fds241053,
Author = {Griffin, NL and Miller, CE and Schmitt, D and D'Août,
K},
Title = {Understanding the evolution of the windlass mechanism of the
human foot from comparative anatomy: Insights, obstacles,
and future directions.},
Journal = {American journal of physical anthropology},
Volume = {156},
Number = {1},
Pages = {1-10},
Year = {2015},
Month = {January},
ISSN = {0002-9483},
Abstract = {Humans stand alone from other primates in that we propel our
bodies forward on a relatively stiff and arched foot and do
so by employing an anatomical arrangement of bones and
ligaments in the foot that can operate like a "windlass."
This is a significant evolutionary innovation, but it is
currently unknown when during hominin evolution this
mechanism developed and within what genera or species it
originated. The presence of recently discovered fossils
along with novel research in the past two decades have
improved our understanding of foot mechanics in humans and
other apes, making it possible to consider this question
more fully. Here we review the main elements thought to be
involved in the production of an effective, modern
human-like windlass mechanism. These elements are the
triceps surae, plantar aponeurosis, medial longitudinal
arch, and metatarsophalangeal joints. We discuss what is
presently known about the evolution of these features and
the challenges associated with identifying each of these
specific components and/or their function in living and
extinct primates for the purpose of predicting the presence
of the windlass mechanism in our ancestors. In some cases we
recommend alternative pathways for inferring foot mechanics
and for testing the hypothesis that the windlass mechanism
evolved to increase the speed and energetic efficiency of
bipedal gait in hominins.},
Doi = {10.1002/ajpa.22636},
Key = {fds241053}
}
@article{fds241052,
Author = {Wunderlich, RE and Tongen, A and Gardiner, J and Miller, CE and Schmitt,
D},
Title = {Dynamics of locomotor transitions from arboreal to
terrestrial substrates in Verreaux's sifaka (Propithecus
verreauxi).},
Journal = {Integrative and comparative biology},
Volume = {54},
Number = {6},
Pages = {1148-1158},
Year = {2014},
Month = {December},
ISSN = {1540-7063},
Abstract = {Most primates are able to move with equal facility on the
ground and in trees, but most use the same quadrupedal gaits
in both environments. A few specialized primates, however,
use a suspensory or leaping mode of locomotion when in the
trees but a bipedal gait while on the ground. This is a rare
behavioral pattern among mammals, and the extent to which
the bipedal gaits of these primates converge and are
constrained by the anatomical and neurological adaptations
associated with arboreal locomotion is poorly understood.
Sifakas (Propithecus), primates living only in Madagascar,
are highly committed vertical clingers and leapers that also
spend a substantial amount of time on the ground. When
moving terrestrially sifakas use a unique bipedal galloping
gait seen in no other mammals. Little research has examined
the mechanics of these gaits, and most of that research has
been restricted to controlled captive conditions. The
energetic costs associated with leaping and bipedal
galloping are unknown. This study begins to fill that gap
using triaxial accelerometry to characterize and compare the
dynamics of sifakas' leaping and bipedal galloping behavior.
As this is a relatively novel approach, the first goal of
this article is to explore the feasibility of collecting
such data on free-roaming animals and attempt to automate
the identification of leaping and bipedal behavior within
the output. The second goal is to compare the overall
accelerations of the body and to use that as an
approximation of aspects of energetic costs during leaping
and bipedalism. To achieve this, a lightweight accelerometer
was mounted on freely moving sifakas. The resulting
acceleration profiles were processed, and sequences of leaps
(bouts) were automatically extracted from the waveforms with
85% accuracy. Both vector dynamic body acceleration and
overall dynamic body acceleration (ODBA) were used to
characterize locomotor patterns and energy expenditure
during leaping and bipedalism. The unique kinematics of the
gait of sifakas, and the mechanics of bouts involving a
string of successive leaps or gallops, appear to minimize
redirections of the center of mass as well as the number of
acceleration peaks and ODBAs. These results suggest that
bipedal galloping is not only a reflection of the unique
anatomical configuration of a leaping primate, but it may
also provide a musculoskeletal and an energetic advantage to
sifakas. In that sense, bipedal galloping represents an
advantageous way for sifakas to move when transitioning from
arboreal leaping to terrestrial locomotion.},
Doi = {10.1093/icb/icu110},
Key = {fds241052}
}
@article{fds241058,
Author = {Granatosky, MC and Miller, CE and Boyer, DM and Schmitt,
D},
Title = {Lumbar vertebral morphology of flying, gliding, and
suspensory mammals: implications for the locomotor behavior
of the subfossil lemurs Palaeopropithecus and
Babakotia.},
Journal = {Journal of human evolution},
Volume = {75},
Pages = {40-52},
Year = {2014},
Month = {October},
ISSN = {0047-2484},
Abstract = {Lumbar vertebral morphology has been used as an indicator of
locomotor behavior in living and fossil mammals. Rigidity
within the lumbar region is thought to be important for
increasing overall axial rigidity during various forms of
locomotion, including bridging between supports, inverted
quadrupedalism, gliding, and flying. However, distinguishing
between those behaviors using bony features has been
challenging. This study used osteological characters of the
lumbar vertebrae to attempt to develop fine-grade functional
distinctions among different mammalian species in order to
make more complete inferences about how the axial skeleton
affects locomotor behavior in extant mammals. These same
lumbar characters were measured in two extinct species for
which locomotor behaviors are well known, the sloth lemurs
(Palaeopropithecus and Babakotia radofilai), in order to
further evaluate their locomotor behaviors. Results from a
principal components analysis of seven measurements,
determined to be functionally significant from previous
studies, demonstrate that inverted quadrupeds in the sample
are characterized by dorsoventrally short and
cranio-caudally expanded spinous processes, dorsally
oriented transverse processes, and mediolaterally short and
dorsoventrally high vertebral bodies compared with mammals
that are relatively pronograde, vertical clingers, or
gliders. Antipronograde mammals, dermopterans, and
chiropterans also exhibit these traits, but not to the same
extent as the inverted quadrupeds. In accordance with
previous studies, our data show that the sloth lemur
B. radofilai groups closely with antipronograde mammals
like lorises, while Palaeopropithecus groups with extant
sloths. These findings suggest that Palaeopropithecus was
engaged in inverted quadrupedalism at a high frequency,
while B. radofilai may have engaged in a more diverse array
of locomotor and positional behaviors. The osteological
features used here reflect differences in lumbar mobility
and suggest that axial rigidity is advantageous for
suspensory locomotion and possibly flight in
bats.},
Doi = {10.1016/j.jhevol.2014.06.011},
Key = {fds241058}
}
@article{fds241061,
Author = {Sparling, TL and Schmitt, D and Miller, CE and Guilak, F and Somers, TJ and Keefe, FJ and Queen, RM},
Title = {Energy recovery in individuals with knee
osteoarthritis.},
Journal = {Osteoarthritis Cartilage},
Volume = {22},
Number = {6},
Pages = {747-755},
Year = {2014},
Month = {June},
ISSN = {1063-4584},
url = {http://hdl.handle.net/10161/8901 Duke open access
repository},
Abstract = {OBJECTIVE: Pathological gaits have been shown to limit
transfer between potential (PE) and kinetic (KE) energy
during walking, which can increase locomotor costs. The
purpose of this study was to examine whether energy exchange
would be limited in people with knee osteoarthritis (OA).
METHODS: Ground reaction forces during walking were
collected from 93 subjects with symptomatic knee OA
(self-selected and fast speeds) and 13 healthy controls
(self-selected speed) and used to calculate their center of
mass (COM) movements, PE and KE relationships, and energy
recovery during a stride. Correlations and linear
regressions examined the impact of energy fluctuation phase
and amplitude, walking velocity, body mass, self-reported
pain, and radiographic severity on recovery. Paired t-tests
were run to compare energy recovery between cohorts.
RESULTS: Symptomatic knee OA subjects displayed lower
energetic recovery during self-selected walking speeds than
healthy controls (P = 0.0018). PE and KE phase
relationships explained the majority (66%) of variance in
recovery. Recovery had a complex relationship with velocity
and its change across speeds was significantly influenced by
the self-selected walking speed of each subject. Neither
radiographic OA scores nor subject self-reported measures
demonstrated any relationship with energy recovery.
CONCLUSIONS: Knee OA reduces effective exchange of PE and
KE, potentially increasing the muscular work required to
control movements of the COM. Gait retraining may return
subjects to more normal patterns of energy exchange and
allow them to reduce fatigue.},
Doi = {10.1016/j.joca.2014.04.004},
Key = {fds241061}
}
@article{fds241066,
Author = {Granatosky, MC and Lemelin, P and Chester, SGB and Pampush, JD and Schmitt, D},
Title = {Functional and evolutionary aspects of axial stability in
euarchontans and other mammals.},
Journal = {Journal of morphology},
Volume = {275},
Number = {3},
Pages = {313-327},
Year = {2014},
Month = {March},
ISSN = {0362-2525},
Keywords = {arboreal • back • locomotion • primates
• ribs • vertebra},
Abstract = {The presence of a stable thoracolumbar region, found in many
arboreal mammals, is considered advantageous for bridging
and cantilevering between discontinuous branches. However,
no study has directly explored the link between osteological
features cited as enhancing axial stability and the
frequency of cantilevering and bridging behaviors in a
terminal branch environment. To fill this gap, we collected
metric data on costal and vertebral morphology of primate
and nonprimate mammals known to cantilever and bridge
frequently and those that do not. We also quantified the
frequency and duration of cantilevering and bridging
behaviors using experimental setups for species that have
been reported to show differences in use of small branches
and back anatomy (Caluromys philander, Loris tardigradus,
Monodelphis domestica, and Cheirogaleus medius).
Phylogenetically corrected principal component analysis
reveals that taxa employing frequent bridging and
cantilevering (C. philander and lorises) also exhibit
reduced intervertebral and intercostal spaces, which can
serve to increase thoracolumbar stability, when compared to
closely related species (M. domestica and C. medius). We
observed C. philander cantilevering and bridging
significantly more often than M. domestica, which never
cantilevered or crossed any arboreal gaps. Although no
difference in the frequency of cantilevering was observed
between L. tardigradus and C. medius, the duration of
cantilevering bouts was significantly greater in L.
tardigradus. These data suggest that osteological features
promoting axial rigidity may be part of a morpho-behavioral
complex that increases stability in mammals moving and
foraging in a terminal branch environment.},
Language = {ENG},
Doi = {10.1002/jmor.20216},
Key = {fds241066}
}
@article{fds241059,
Author = {McNeill, JN and Wu, C-L and Rabey, KN and Schmitt, D and Guilak,
F},
Title = {Life-long caloric restriction does not alter the severity of
age-related osteoarthritis.},
Journal = {Age (Dordr)},
Volume = {36},
Number = {4},
Pages = {9669},
Year = {2014},
ISSN = {0161-9152},
Abstract = {Chronic adipose tissue inflammation and its associated
adipokines have been linked to the development of
osteoarthritis (OA). It has been shown that caloric
restriction may decrease body mass index and adiposity. The
objectives of this study were to investigate the effect of
lifelong caloric restriction on bone morphology, joint
inflammation, and spontaneously occurring OA development in
aged mice. C57BL/NIA mice were fed either a
calorie-restricted (CR) or ad libitum (AL) diet starting at
14 weeks of age. All mice were sacrificed at 24 months of
age. Adipose tissue and knee joints were then harvested.
Bone parameters of the joints were analyzed by micro-CT. OA
and joint synovitis were determined using histology and
semiquantitative analysis. Lifelong caloric restriction did
not alter the severity of OA development in C57BL/NIA aged
mice, and there was no difference in the total joint Mankin
score between CR and AL groups (p = 0.99). Mice also
exhibited similar levels of synovitis (p = 0.54). The bone
mineral density of the femur and the tibia was comparable
between the groups with a small increase in cancellous bone
volume fraction in the lateral femoral condyle of the CR
group compared with the AL group. Lifelong caloric
restriction did not alter the incidence of OA or joint
synovitis in C57BL/NIA mice, indicating that a reduction of
caloric intake alone was not sufficient to prevent
spontaneous age-related OA. Nonetheless, early initiation of
CR continued throughout a life span did not negatively
impact bone structural properties.},
Doi = {10.1007/s11357-014-9669-5},
Key = {fds241059}
}
@article{fds241068,
Author = {Griffin, NL and Miller, C and Schmitt, D and D'Août,
K},
Title = {An investigation of the dynamic relationship between
navicular drop and first metatarsophalangeal joint dorsal
excursion.},
Journal = {Journal of anatomy},
Volume = {222},
Number = {6},
Pages = {598-607},
Year = {2013},
Month = {June},
ISSN = {0021-8782},
Keywords = {Adult • Aged • Female • Foot • Gait
• Humans • India • Male •
Metatarsophalangeal Joint • Middle Aged •
Pronation • Regression Analysis • Tarsal Bones
• Walking • Young Adult • anatomy & histology
• physiology • physiology*},
Abstract = {The modern human foot is a complex biomechanical structure
that must act both as a shock absorber and as a propulsive
strut during the stance phase of gait. Understanding the
ways in which foot segments interact can illuminate the
mechanics of foot function in healthy and pathological
humans. It has been proposed that increased values of medial
longitudinal arch deformation can limit metatarsophalangeal
joint excursion via tension in the plantar aponeurosis.
However, this model has not been tested directly in a
dynamic setting. In this study, we tested the hypothesis
that during the stance phase, subtalar pronation (stretching
of the plantar aponeurosis and subsequent lowering of the
medial longitudinal arch) will negatively affect the amount
of first metatarsophalangeal joint excursion occurring at
push-off. Vertical descent of the navicular (a proxy for
subtalar pronation) and first metatarsophalangeal joint
dorsal excursion were measured during steady locomotion over
a flat substrate on a novel sample consisting of
asymptomatic adult males and females, many of whom are
habitually unshod. Least-squares regression analyses
indicated that, contrary to the hypothesis, navicular drop
did not explain a significant amount of variation in first
metatarsophalangeal joint dorsal excursion. These results
suggest that, in an asymptomatic subject, the plantar
aponeurosis and the associated foot bones can function
effectively within the normal range of subtalar pronation
that takes place during walking gait. From a clinical
standpoint, this study highlights the need for investigating
the in vivo kinematic relationship between subtalar
pronation and metatarsophalangeal joint dorsiflexion in
symptomatic populations, and also the need to explore other
factors that may affect the kinematics of asymptomatic
feet.},
Language = {eng},
Doi = {10.1111/joa.12050},
Key = {fds241068}
}
@article{fds241062,
Author = {O'Neill, MC and Schmitt, D},
Title = {Erratum: The gaits of primates: Center of mass mechanics in
walking, cantering and galloping ring-tailed lemurs, Lemur
catta ((1994) Journal of Experimental Biology 215
(1728-1739))},
Journal = {Journal of Experimental Biology},
Volume = {215},
Number = {11},
Pages = {1994},
Publisher = {The Company of Biologists},
Year = {2012},
Month = {June},
ISSN = {0022-0949},
Doi = {10.1242/jeb.074500},
Key = {fds241062}
}
@article{fds241085,
Author = {Somers, TJ and Blumenthal, JA and Guilak, F and Kraus, VB and Schmitt,
DO and Babyak, MA and Craighead, LW and Caldwell, DS and Rice, JR and McKee, DC and Shelby, RA and Campbell, LC and Pells, JJ and Sims, EL and Queen, R and Carson, JW and Connelly, M and Dixon, KE and LaCaille, LJ and Huebner, JL and Rejeski, JW and Keefe, FJ},
Title = {Pain coping skills training and lifestyle behavioral weight
management in patients with knee osteoarthritis: a
randomized controlled study.},
Journal = {Pain},
Volume = {153},
Number = {6},
Pages = {1199-1209},
Year = {2012},
Month = {June},
ISSN = {1872-6623},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22503223},
Abstract = {Overweight and obese patients with osteoarthritis (OA)
experience more OA pain and disability than patients who are
not overweight. This study examined the long-term efficacy
of a combined pain coping skills training (PCST) and
lifestyle behavioral weight management (BWM) intervention in
overweight and obese OA patients. Patients (n=232) were
randomized to a 6-month program of: 1) PCST+BWM; 2)
PCST-only; 3) BWM-only; or 4) standard care control.
Assessments of pain, physical disability (Arthritis Impact
Measurement Scales [AIMS] physical disability, stiffness,
activity, and gait), psychological disability (AIMS
psychological disability, pain catastrophizing, arthritis
self-efficacy, weight self-efficacy), and body weight were
collected at 4 time points (pretreatment, posttreatment, and
6 months and 12 months after the completion of treatment).
Patients randomized to PCST+BWM demonstrated significantly
better treatment outcomes (average of all 3 posttreatment
values) in terms of pain, physical disability, stiffness,
activity, weight self-efficacy, and weight when compared to
the other 3 conditions (Ps<0.05). PCST+BWM also did
significantly better than at least one of the other
conditions (ie, PCST-only, BWM-only, or standard care) in
terms of psychological disability, pain catastrophizing, and
arthritis self-efficacy. Interventions teaching overweight
and obese OA patients pain coping skills and weight
management simultaneously may provide the more comprehensive
long-term benefits.},
Language = {eng},
Doi = {10.1016/j.pain.2012.02.023},
Key = {fds241085}
}
@article{fds241081,
Author = {O'Neill, MC and Schmitt, D},
Title = {The gaits of primates: center of mass mechanics in walking,
cantering and galloping ring-tailed lemurs, Lemur
catta.},
Journal = {The Journal of experimental biology},
Volume = {215},
Number = {Pt 10},
Pages = {1728-1739},
Year = {2012},
Month = {May},
ISSN = {0022-0949},
Keywords = {Algorithms • Animals • Behavior, Animal •
Biomechanics • Female • Gait • Gravitation
• Kinetics • Lemur • Male • Models,
Statistical • Movement • Primates • Running*
• Walking* • physiology*},
Abstract = {Most primates, including lemurs, have a broad range of
locomotor capabilities, yet much of the time, they walk at
slow speeds and amble, canter or gallop at intermediate and
fast speeds. Although numerous studies have investigated
limb function during primate quadrupedalism, how the center
of mass (COM) moves is not well understood. Here, we
examined COM energy, work and power during walking,
cantering and galloping in ring-tailed lemurs, Lemur catta
(N=5), over a broad speed range (0.43-2.91 m s(-1)). COM
energy recoveries were substantial during walking (35-71%)
but lower during canters and gallops (10-51%). COM work,
power and collisional losses increased with speed. The
positive COM works were 0.625 J kg(-1) m(-1) for walks and
1.661 J kg(-1) m(-1) for canters and gallops, which are in
the middle range of published values for terrestrial
animals. Although some discontinuities in COM mechanics were
evident between walking and cantering, there was no apparent
analog to the trot-gallop transition across the intermediate
and fast speed range (dimensionless v>0.75, Fr>0.5). A
phenomenological model of a lemur cantering and trotting at
the same speed shows that canters ensure continuous contact
of the body with the substrate while reducing peak vertical
COM forces, COM stiffness and COM collisions. We suggest
that cantering, rather than trotting, at intermediate speeds
may be tied to the arboreal origins of the Order Primates.
These data allow us to better understand the mechanics of
primate gaits and shed new light on primate locomotor
evolution.},
Language = {eng},
Doi = {10.1242/jeb.052340},
Key = {fds241081}
}
@article{fds241086,
Author = {Allen, KD and Mata, BA and Gabr, MA and Huebner, JL and Adams, SB and Kraus, VB and Schmitt, DO and Setton, LA},
Title = {Kinematic and dynamic gait compensations resulting from knee
instability in a rat model of osteoarthritis.},
Journal = {Arthritis Res Ther},
Volume = {14},
Number = {2},
Pages = {R78},
Year = {2012},
Month = {April},
ISSN = {1478-6362},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22510443},
Abstract = {INTRODUCTION: Osteoarthritis (OA) results in pain and
disability; however, preclinical OA models often focus on
joint-level changes. Gait analysis is one method used to
evaluate both preclinical OA models and OA patients. The
objective of this study is to describe spatiotemporal and
ground reaction force changes in a rat medial meniscus
transection (MMT) model of knee OA and to compare these gait
measures with assays of weight bearing and tactile
allodynia. METHODS: Sixteen rats were used in the study. The
medial collateral ligament (MCL) was transected in twelve
Lewis rats (male, 200 to 250 g); in six rats, the medial
meniscus was transected, and the remaining six rats served
as sham controls. The remaining four rats served as naïve
controls. Gait, weight-bearing as measured by an
incapacitance meter, and tactile allodynia were assessed on
postoperative days 9 to 24. On day 28, knee joints were
collected for histology. Cytokine concentrations in the
serum were assessed with a 10-plex cytokine panel. RESULTS:
Weight bearing was not affected by sham or MMT surgery;
however, the MMT group had decreased mechanical
paw-withdrawal thresholds in the operated limb relative to
the contralateral limb (P = 0.017). The gait of the MMT
group became increasingly asymmetric from postoperative days
9 to 24 (P = 0.020); moreover, MMT animals tended to spend
more time on their contralateral limb than their operated
limb while walking (P < 0.1). Ground reaction forces
confirmed temporal shifts in symmetry and stance time, as
the MMT group had lower vertical and propulsive ground
reaction forces in their operated limb relative to the
contralateral limb, naïve, and sham controls (P < 0.05).
Levels of interleukin 6 in the MMT group tended to be higher
than naïve controls (P = 0.072). Histology confirmed
increased cartilage damage in the MMT group, consistent with
OA initiation. Post hoc analysis revealed that gait
symmetry, stance time imbalance, peak propulsive force, and
serum interleukin 6 concentrations had significant
correlations to the severity of cartilage lesion formation.
CONCLUSION: These data indicate significant gait
compensations were present in the MMT group relative to
medial collateral ligament (MCL) injury (sham) alone and
naïve controls. Moreover, these data suggest that gait
compensations are likely driven by meniscal instability
and/or cartilage damage, and not by MCL injury
alone.},
Language = {eng},
Doi = {10.1186/ar3801},
Key = {fds241086}
}
@article{fds241079,
Author = {Workman, C and Schmitt, D},
Title = {Erratum to: Positional Behavior of Delacour's Langurs
(Trachypithecus delacouri) in Northern Vietnam (Int J
Primatol, 10.1007/s10764-011-9547-2)},
Journal = {International Journal of Primatology},
Volume = {33},
Number = {1},
Pages = {38-39},
Publisher = {Springer Nature},
Year = {2012},
Month = {February},
ISSN = {0164-0291},
Doi = {10.1007/s10764-012-9577-4},
Key = {fds241079}
}
@article{fds241080,
Author = {Workman, C and Schmitt, D},
Title = {Positional Behavior of Delacour's Langurs (Trachypithecus
delacouri) in Northern Vietnam},
Journal = {International Journal of Primatology},
Volume = {33},
Number = {1},
Pages = {19-37},
Publisher = {Springer Nature},
Year = {2012},
Month = {January},
ISSN = {0164-0291},
Abstract = {Information on positional behavior can help elucidate
relationships between a species' morphology, behavior, and
environment. Delacour's langurs (Trachypithecus delacouri)
are similar to other colobines in body mass and intermembral
index, yet inhabit a limestone karst environment. From
August 2007 to July 2008, we collected 372 h of positional
behavior and substrate use data from 8 groups of
Trachypithecus delacouri in Van Long Nature Reserve, Vietnam
to address questions about how the distinct -and potentially
dangerous- features of karst influence colobine positional
behavior. Results show that Trachypithecus delacouri is
predominantly quadrupedal (66%). However, they exhibit
differences that set them apart from many other colobines.
Nearly 80% of locomotor and postural behaviors were
performed on rocks. Leaping was remarkably infrequent,
representing only 6% of overall locomotion. They leapt 3
times more frequently on trees (13%) than on rocks (4%) and
more frequently used trees as a landing substrate than rocks
(38% vs. 23%), both significant differences. We argue that
rock (and cliff) travel is altogether different from
terrestrial and arboreal travel and propose using the term
petrous to indicate the substrate and incorporate the
implications of its precise sharpness and verticality that
lead to the complexities and risk of locomotion on rock
surfaces. Trachypithecus delacouri does not show specific
adaptations for limestone karst. Instead they appear to be a
behaviorally flexible species and, owing to the generalized
locomotor capabilities that characterize cercopithecids,
capable of locomoting through and living in the limestone
rock environment to which they have relatively recently been
restricted. © 2011 Springer Science+Business Media,
LLC.},
Doi = {10.1007/s10764-011-9547-2},
Key = {fds241080}
}
@article{fds241093,
Author = {Allen, KD and Shamji, MF and Mata, BA and Gabr, MA and Sinclair, SM and Schmitt, DO and Richardson, WJ and Setton, LA},
Title = {Kinematic and dynamic gait compensations in a rat model of
lumbar radiculopathy and the effects of tumor necrosis
factor-alpha antagonism.},
Journal = {Arthritis Res Ther},
Volume = {13},
Number = {4},
Pages = {R137},
Year = {2011},
Month = {August},
ISSN = {1478-6362},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21871102},
Abstract = {INTRODUCTION: Tumor necrosis factor-α (TNFα) has received
significant attention as a mediator of lumbar radiculopathy,
with interest in TNF antagonism to treat radiculopathy.
Prior studies have demonstrated that TNF antagonists can
attenuate heightened nociception resulting from lumbar
radiculopathy in the preclinical model. Less is known about
the potential impact of TNF antagonism on gait
compensations, despite being of clinical relevance. In this
study, we expand on previous descriptions of gait
compensations resulting from lumbar radiculopathy in the rat
and describe the ability of local TNF antagonism to prevent
the development of gait compensations, altered weight
bearing, and heightened nociception. METHODS: Eighteen male
Sprague-Dawley rats were investigated for mechanical
sensitivity, weight-bearing, and gait pre- and
post-operatively. For surgery, tail nucleus pulposus (NP)
tissue was collected and the right L5 dorsal root ganglion
(DRG) was exposed (Day 0). In sham animals, NP tissue was
discarded (n = 6); for experimental animals, autologous NP
was placed on the DRG with or without 20 μg of soluble TNF
receptor type II (sTNFRII, n = 6 per group). Spatiotemporal
gait characteristics (open arena) and mechanical sensitivity
(von Frey filaments) were assessed on post-operative Day 5;
gait dynamics (force plate arena) and weight-bearing
(incapacitance meter) were assessed on post-operative Day 6.
RESULTS: High-speed gait characterization revealed animals
with NP alone had a 5% decrease in stance time on their
affected limbs on Day 5 (P ≤0.032). Ground reaction force
analysis on Day 6 aligned with temporal changes observed on
Day 5, with vertical impulse reduced in the affected limb of
animals with NP alone (area under the vertical force-time
curve, P <0.02). Concordant with gait, animals with NP alone
also had some evidence of affected limb mechanical allodynia
on Day 5 (P = 0.08) and reduced weight-bearing on the
affected limb on Day 6 (P <0.05). Delivery of sTNFRII at the
time of NP placement ameliorated signs of mechanical
hypersensitivity, imbalanced weight distribution, and gait
compensations (P <0.1). CONCLUSIONS: Our data indicate gait
characterization has value for describing early limb
dysfunctions in pre-clinical models of lumbar radiculopathy.
Furthermore, TNF antagonism prevented the development of
gait compensations subsequent to lumbar radiculopathy in our
model.},
Language = {eng},
Doi = {10.1186/ar3451},
Key = {fds241093}
}
@article{fds241089,
Author = {Hanna, JB and Schmitt, D},
Title = {Locomotor energetics in primates: gait mechanics and their
relationship to the energetics of vertical and horizontal
locomotion.},
Journal = {American journal of physical anthropology},
Volume = {145},
Number = {1},
Pages = {43-54},
Year = {2011},
Month = {May},
ISSN = {0002-9483},
Keywords = {Air • Animals • Body Weight • Energy
Metabolism • Gait • Locomotion • Oxygen
• Oxygen Consumption • Saimiri • Strepsirhini
• Video Recording • analysis • metabolism
• physiology*},
Abstract = {All primates regularly move within three-dimensional
arboreal environments and must often climb, but little is
known about the energetic costs of this critical activity.
Limited previous work on the energetics of incline
locomotion suggests that there may be differential selective
pressures for large compared to small primates in choosing
to exploit a complex arboreal environment. Necessary
metabolic and gait data have never been collected to examine
this possibility and biomechanical mechanisms that might
explain size-based differences in the cost of arboreal
movement. Energetics and kinematics were collected for five
species of primate during climbing and horizontal
locomotion. Subjects moved on a treadmill with a narrow
vertical substrate and one with a narrow horizontal
substrate at their maximum sustainable speed for 10–20 min
while oxygen consumption was monitored. Data during climbing
were compared to those during horizontal locomotion and
across size. Results show that climbing energetic costs were
similar to horizontal costs for small primates (<0.5 kg) but
were nearly double for larger species. Spatio-temporal gait
characteristics suggest that the relationship between the
cost of locomotion and the rate of force production changes
between the two locomotor modes. Thus, the main determinants
of climbing costs are fundamentally different from those
during horizontal locomotion. These new results combining
spatiotemporal and energetic data confirm and expand on our
previous argument (Hanna et al.: Science 320 (2008) 898)
that similar costs of horizontal and vertical locomotion in
small primates facilitated the successful occupation of a
fine-branch arboreal milieu by the earliest
primates.},
Language = {eng},
Doi = {10.1002/ajpa.21465},
Key = {fds241089}
}
@article{springerlink:10.1007/s10764-010-9479-2,
Author = {Hanna, JB and Schmitt, D},
Title = {Interpreting the Role of Climbing in Primate Locomotor
Evolution: Are the Biomechanics of Climbing Influenced by
Habitual Substrate Use and Anatomy?},
Journal = {International Journal of Primatology},
Volume = {32},
Number = {2},
Pages = {430-444},
Publisher = {Springer Nature},
Organization = {Department of Biomedical Sciences, West Virginia School of
Osteopathic Medicine, Lewisburg, WV 24901,
USA},
Institution = {Department of Biomedical Sciences, West Virginia School of
Osteopathic Medicine, Lewisburg, WV 24901,
USA},
Year = {2011},
Month = {April},
ISSN = {0164-0291},
url = {http://dx.doi.org/10.1007/s10764-010-9479-2},
Abstract = {Vertical climbing is widely accepted to have played an
important role in the origins of both primate locomotion and
of human bipedalism. Yet, only a few researchers have
compared climbing mechanics in quadrupedal primates that
vary in their degree of arboreality. It is assumed that
primates using vertical climbing with a relatively high
frequency will have morphological and behavioral
specializations that facilitate efficient climbing
mechanics. We test this assumption by examining whether time
spent habitually engaged in climbing influences locomotor
parameters such as footfall sequence, peak forces, and joint
excursions during vertical climbing. Previous studies have
shown that during climbing, the pronograde and
semiterrestrial Macaca fuscata differs in these parameters
compared to the more arboreal and highly specialized,
antipronograde Ateles geoffroyi. Here, we examine whether a
fully arboreal, quadrupedal primate that does not regularly
arm-swing will exhibit gait and force distribution patterns
intermediate between those of Macaca fuscata and Ateles
geoffroyi. We collected footfall sequence, limb peak
vertical forces, and 3D hindlimb excursion data for Macaca
fascicularis during climbing on a stationary pole
instrumented with a force transducer. Results show that
footfall sequences are similar between macaque species,
whereas peak force distributions and hindlimb excursions for
Macaca fascicularis are intermediate between values reported
for M. fuscata and Ateles geoffroyi. These results support
the notion that time spent climbing is reflected in climbing
mechanics, even though morphology may not provide for
efficient mechanics, and highlight the important role of
arboreal locomotor activity in determining the pathways of
primate locomotor evolution. © 2010 Springer
Science+Business Media, LLC.},
Doi = {10.1007/s10764-010-9479-2},
Key = {springerlink:10.1007/s10764-010-9479-2}
}
@article{ref1,
Author = {Hanna, JB and Schmitt, D},
Title = {Comparative Triceps Surae Morphology in Primates: A
Review},
Journal = {Anatomy Research International},
Volume = {2011},
Pages = {1-22},
Publisher = {Hindawi Limited},
Year = {2011},
url = {http://dx.doi.org/10.1155/2011/191509},
Abstract = {<jats:p>Primate locomotor evolution, particularly the
evolution of bipedalism, is often examined through
morphological studies. Many of these studies have examined
the uniqueness of the primate forelimb, and others have
examined the primate hip and thigh. Few data exist, however,
regarding the myology and function of the leg muscles, even
though the ankle plantar flexors are highly important during
human bipedalism. In this paper, we draw together data on
the fiber type and muscle mass variation in the ankle
plantar flexors of primates and make comparisons to other
mammals. The data suggest that great apes, atelines, and
lorisines exhibit similarity in the mass distribution of the
triceps surae. We conclude that variation in triceps surae
may be related to the shared locomotor mode exhibited by
these groups and that triceps surae morphology, which
approaches that of humans, may be related to frequent use of
semiplantigrade locomotion and vertical climbing.</jats:p>},
Doi = {10.1155/2011/191509},
Key = {ref1}
}
@article{fds241094,
Author = {Schmitt, D and Zumwalt, AC and Hamrick, MW},
Title = {The relationship between bone mechanical properties and
ground reaction forces in normal and hypermuscular
mice.},
Journal = {Journal of experimental zoology. Part A, Ecological genetics
and physiology},
Volume = {313},
Number = {6},
Pages = {339-351},
Year = {2010},
Month = {July},
ISSN = {1932-5223},
Keywords = {Animals • Biomechanics • Bone and Bones •
Mice • Muscle, Skeletal • Organ Size •
physiology*},
Abstract = {Understanding the relationship between external load and
bone morphology is critical for understanding adaptations to
load in extant animals and inferring behavior in extinct
forms. Yet, the relationship between bony anatomy and load
is poorly understood, with empirical studies often producing
conflicting results. It is widely assumed in many ecological
and paleontological studies that bone size and strength
reflect the forces experienced by the bone in vivo. This
study examines that assumption by providing preliminary data
on gait mechanics in a hypermuscular myostatin-deficient
mouse model with highly mineralized and hypertrophied long
bones. A small sample of hypermuscular and wild-type mice
was video recorded while walking freely across a force
platform. Temporal gait parameters, peak vertical and
transverse (mediolateral) ground reaction forces (GRFs),
vertical impulse, and loading rates were measured. The only
gait parameters that differed between the two groups were
the speeds at which the animals traveled and the transverse
forces on the hind limb. The myostatin-deficient mice move
relatively slowly and experienced the same magnitude of
vertical forces on all limbs and transverse forces on the
forelimb as the wild-type mice; though the
myostatin-deficient mice did experience lower mediolateral
forces on their hindlimbs compared with the wild-type mice.
These preliminary results call into question the hypothesis
that skeletal hypertrophy observed in hypermuscular mice is
a result of larger GRFs experienced by the animals' limbs
during locomotion. This calls for further analysis and a
cautious approach to inferences about locomotor behavior
derived from bony morphology in extant and fossil
species.},
Language = {eng},
Doi = {10.1002/jez.604},
Key = {fds241094}
}
@article{fds241096,
Author = {Kivell, TL and Schmitt, D and Wunderlich, RE},
Title = {Hand and foot pressures in the aye-aye (Daubentonia
madagascariensis) reveal novel biomechanical trade-offs
required for walking on gracile digits.},
Journal = {The Journal of experimental biology},
Volume = {213},
Number = {Pt 9},
Pages = {1549-1557},
Year = {2010},
Month = {May},
ISSN = {0022-0949},
url = {http://hdl.handle.net/10161/4193 Duke open access
repository},
Keywords = {Animals • Biomechanics • Foot • Hand •
Posture • Strepsirhini • Walking* •
physiology • physiology*},
Abstract = {Arboreal animals with prehensile hands must balance the
complex demands of bone strength, grasping and manipulation.
An informative example of this problem is that of the
aye-aye (Daubentonia madagascariensis), a rare lemuriform
primate that is unusual in having exceptionally long,
gracile fingers specialized for foraging. In addition, they
are among the largest primates to engage in head-first
descent on arboreal supports, a posture that should increase
loads on their gracile digits. We test the hypothesis that
aye-ayes will reduce pressure on their digits during
locomotion by curling their fingers off the substrate. This
hypothesis was tested using simultaneous videographic and
pressure analysis of the hand, foot and digits for five
adult aye-ayes during horizontal locomotion and during
ascent and descent on a 30 degrees instrumented runway.
Aye-ayes consistently curled their fingers during locomotion
on all slopes. When the digits were in contact with the
substrate, pressures were negligible and significantly less
than those experienced by the palm or pedal digits. In
addition, aye-ayes lifted their hands vertically off the
substrate instead of 'toeing-off' and descended head-first
at significantly slower speeds than on other slopes.
Pressure on the hand increased during head-first descent
relative to horizontal locomotion but not as much as the
pressure increased on the foot during ascent. This
distribution of pressure suggests that aye-ayes shift their
weight posteriorly during head-first descent to reduce loads
on their gracile fingers. This research demonstrates several
novel biomechanical trade-offs to deal with complex
functional demands on the mammalian skeleton.},
Language = {eng},
Doi = {10.1242/jeb.040014},
Key = {fds241096}
}
@article{fds241050,
Author = {Schmitt, D},
Title = {Primate Locomotor Evolution: Biomechanical Studies of
Primate Locomotion and Their Implications for Understanding
Primate Neuroethology},
Pages = {31-63},
Publisher = {Oxford University Press},
Year = {2010},
Month = {February},
Abstract = {This chapter argues that primates (including humans) show
patterns of locomotion and locomotor control that are
different from all other mammals. Changes in limb function
associated with the adaptive diversification of locomotor
patterns in the primate clade probably required the
evolution of profound specializations in the neural control
of locomotion. Most of these putative specializations remain
unknown or unexplored. This realization suggests that
comparative studies of the neuroethology of locomotion in
primates may offer unique insights into motor control, and
such insights may have implications for fields as diverse as
robotics and the clinical treatment of paralysis with
brain-machine interface devices.},
Doi = {10.1093/acprof:oso/9780195326598.003.0003},
Key = {fds241050}
}
@article{fds241092,
Author = {Schmitt, D and Gruss, LT and Lemelin, P},
Title = {Brief communication: Forelimb compliance in arboreal and
terrestrial opossums.},
Journal = {American journal of physical anthropology},
Volume = {141},
Number = {1},
Pages = {142-146},
Year = {2010},
Month = {January},
ISSN = {0002-9483},
Keywords = {Animals • Behavior, Animal • Biological Evolution
• Biomechanics • Forelimb • Locomotion •
Opossums • anatomy & histology* •
physiology},
Abstract = {Primates display high forelimb compliance (increased elbow
joint yield) compared to most other mammals. Forelimb
compliance, which is especially marked among arboreal
primates, moderates vertical oscillations of the body and
peak vertical forces and may represent a basal adaptation of
primates for locomotion on thin, flexible branches. However,
Larney and Larson (Am J Phys Anthropol 125 [2004] 42-50)
reported that marsupials have forelimb compliance comparable
to or greater than that of most primates, but did not
distinguish between arboreal and terrestrial marsupials. If
forelimb compliance is functionally linked to locomotion on
thin branches, then elbow yield should be highest in
marsupials relying on arboreal substrates more often. To
test this hypothesis, we compared forelimb compliance
between two didelphid marsupials, Caluromys philander (an
arboreal opossum relying heavily on thin branches) and
Monodelphis domestica (an opossum that spends most of its
time on the ground). Animals were videorecorded while
walking on a runway or a horizontal 7-mm pole. Caluromys
showed higher elbow yield (greater changes in degrees of
elbow flexion) on both substrates, similar to that reported
for arboreal primates. Monodelphis was characterized by
lower elbow yield that was intermediate between the values
reported by Larney and Larson (Am J Phys Anthropol 125
[2004] 42-50) for more terrestrial primates and rodents.
This finding adds evidence to a model suggesting a
functional link between arboreality--particularly locomotion
on thin, flexible branches--and forelimb compliance. These
data add another convergent trait between arboreal primates,
Caluromys, and other arboreal marsupials and support the
argument that all primates evolved from a common ancestor
that was a fine-branch arborealist.},
Language = {eng},
Doi = {10.1002/ajpa.21145},
Key = {fds241092}
}
@article{fds241095,
Author = {Sims, EL and Keefe, FJ and Kraus, VB and Guilak, F and Queen, RM and Schmitt, D},
Title = {Racial differences in gait mechanics associated with knee
osteoarthritis.},
Journal = {Aging Clin Exp Res},
Volume = {21},
Number = {6},
Pages = {463-469},
Year = {2009},
Month = {December},
ISSN = {1594-0667},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20154517},
Keywords = {Adult • African Continental Ancestry Group* • Aged
• Anthropometry • Disability Evaluation •
Educational Status • European Continental Ancestry
Group* • Female • Gait • Humans • Knee
Joint • Male • Middle Aged • Osteoarthritis,
Knee • Range of Motion, Articular • Self Concept
• Severity of Illness Index • ethnology* •
physiology • physiology* • physiopathology •
physiopathology*},
Abstract = {BACKGROUND AND AIMS: This study examines racial differences
in gait mechanics in persons with knee osteoarthritis and
the influence of anthropometrics, educational level,
radiographic disease severity (rOA), and self-report
measures of pain and disability on racial differences in
gait. METHODS: One hundred seventy five (64 black and 111
white) adults with radiographic knee OA were tested. 3-D
kinematic and kinetic data were collected while subjects
walked at two self-selected speeds (normal and fast).
Anthropometric data, radiographic level of OA, and
self-report measures of pain and disability were also
collected. Gait patterns were compared across groups and
within groups. RESULTS: Black and white subjects did not
differ significantly in radiographic OA. However, blacks
walked significantly more slowly when asked to walk fast. At
the normal speed, blacks had a smaller knee range of motion
and loading rate than whites. Blacks also took longer to
reach their peak maximum ground reaction force than whites.
Within black subjects variations in gait mechanics were
primarily explained by BMI, rOA, selfreported psychological
disability, and pain self-efficacy. In white subjects,
variations in gait mechanics were primarily explained by
weight, age, velocity, psychological disability, and
self-efficacy. CONCLUSIONS: Blacks in this study had a
pattern of gait mechanics generally associated with high
levels of osteoarthritis, though they did not differ
significantly in rOA from whites. The variability in gait
patterns exhibited by blacks was most strongly related to
variance in walking speed, anthropometrics, and perceived
physical ability. Taken together, these results suggest that
race is an important factor that must be considered in the
treatment and study of osteoarthritis.},
Language = {eng},
Doi = {10.1007/BF03327442},
Key = {fds241095}
}
@article{fds241091,
Author = {Nebel, MB and Sims, EL and Keefe, FJ and Kraus, VB and Guilak, F and Caldwell, DS and Pells, JJ and Queen, R and Schmitt,
D},
Title = {The relationship of self-reported pain and functional
impairment to gait mechanics in overweight and obese persons
with knee osteoarthritis.},
Journal = {Arch Phys Med Rehabil},
Volume = {90},
Number = {11},
Pages = {1874-1879},
Year = {2009},
Month = {November},
ISSN = {1532-821X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19887211},
Keywords = {Disability Evaluation* • Disabled Persons • Female
• Gait • Humans • Male • Middle Aged
• Obesity • Osteoarthritis, Knee •
Overweight* • Pain • Pain Measurement •
Regression Analysis • Self Disclosure •
complications • etiology* • physiology* •
physiopathology*},
Abstract = {OBJECTIVE: To examine the degree to which 2 commonly used
measures of pain and disability, the Arthritis Impact
Measurement Scales (AIMS) and the Western Ontario and
McMaster Universities Osteoarthritis Index (WOMAC), relate
to objective gait measurements. DESIGN: A descriptive study
of the influence of self-reported pain and perceived
functional impairment on gait mechanics in osteoarthritic
adults. SETTING: A university clinical research laboratory.
PARTICIPANTS: Overweight/obese adults with radiographic knee
osteoarthritis (OA) as well as pain and disability
associated with the disease (N=179). INTERVENTIONS: Not
applicable. MAIN OUTCOME MEASURES: The AIMS and WOMAC were
administered to determine self-report measures of pain and
disability. Speed, stride length, support time, knee angle,
and peak vertical force (PVF) were determined from
3-dimensional kinematic and kinetic data collected on
subjects walking at self-selected normal and fast speeds.
Anthropometric data and radiographic levels of OA were also
collected. RESULTS: Pearson correlation analysis showed that
the AIMS physical disability score was inversely correlated
with speed, stride length, and knee range of motion at both
speeds and PVF at the fast speed. The WOMAC function score
was inversely correlated with speed and stride length at
both speeds and with PVF at fast speed. The WOMAC pain score
was inversely correlated with speed and PVF at the fast
speed. Regression analysis revealed that the AIMS physical
disability score and body mass index accounted for the
greatest variation in speed at the normal speed. Overall,
AIMS physical disability and WOMAC function explained a
larger proportion of variance in gait mechanics than
radiographic measures of OA disease severity. CONCLUSIONS:
Taken together, the results suggest that the AIMS physical
disability and WOMAC function scores are associated with
some important measures of gait impairment.},
Language = {eng},
Doi = {10.1016/j.apmr.2009.07.010},
Key = {fds241091}
}
@article{fds241100,
Author = {Kivell, TL and Schmitt, D},
Title = {Independent evolution of knuckle-walking in African apes
shows that humans did not evolve from a knuckle-walking
ancestor.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {106},
Number = {34},
Pages = {14241-14246},
Year = {2009},
Month = {August},
ISSN = {0027-8424},
Keywords = {Animals • Anthropology, Physical • Biological
Evolution* • Fossils • Hominidae • Humans
• Walking • Wrist Joint • anatomy & histology
• physiology • physiology*},
Abstract = {Despite decades of debate, it remains unclear whether human
bipedalism evolved from a terrestrial knuckle-walking
ancestor or from a more generalized, arboreal ape ancestor.
Proponents of the knuckle-walking hypothesis focused on the
wrist and hand to find morphological evidence of this
behavior in the human fossil record. These studies, however,
have not examined variation or development of purported
knuckle-walking features in apes or other primates, data
that are critical to resolution of this long-standing
debate. Here we present novel data on the frequency and
development of putative knuckle-walking features of the
wrist in apes and monkeys. We use these data to test the
hypothesis that all knuckle-walking apes share similar
anatomical features and that these features can be used to
reliably infer locomotor behavior in our extinct ancestors.
Contrary to previous expectations, features long-assumed to
indicate knuckle-walking behavior are not found in all
African apes, show different developmental patterns across
species, and are found in nonknuckle-walking primates as
well. However, variation among African ape wrist morphology
can be clearly explained if we accept the likely independent
evolution of 2 fundamentally different biomechanical modes
of knuckle-walking: an extended wrist posture in an arboreal
environment (Pan) versus a neutral, columnar hand posture in
a terrestrial environment (Gorilla). The presence of
purported knuckle-walking features in the hominin wrist can
thus be viewed as evidence of arboreality, not
terrestriality, and provide evidence that human bipedalism
evolved from a more arboreal ancestor occupying the
ecological niche common to all living apes.},
Language = {eng},
Doi = {10.1073/pnas.0901280106},
Key = {fds241100}
}
@article{fds241099,
Author = {Somers, TJ and Keefe, FJ and Pells, JJ and Dixon, KE and Waters, SJ and Riordan, PA and Blumenthal, JA and McKee, DC and LaCaille, L and Tucker,
JM and Schmitt, D and Caldwell, DS and Kraus, VB and Sims, EL and Shelby,
RA and Rice, JR},
Title = {Pain catastrophizing and pain-related fear in osteoarthritis
patients: relationships to pain and disability.},
Journal = {J Pain Symptom Manage},
Volume = {37},
Number = {5},
Pages = {863-872},
Year = {2009},
Month = {May},
ISSN = {1873-6513},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19041218},
Keywords = {Activities of Daily Living* • Anxiety •
Comorbidity • Disability Evaluation* • Fear*
• Female • Humans • Male • Middle Aged
• North Carolina • Osteoarthritis, Knee •
Pain • Risk Assessment • Risk Factors •
diagnosis • epidemiology • epidemiology* •
methods • psychology},
Abstract = {This study examined the degree to which pain catastrophizing
and pain-related fear explain pain, psychological
disability, physical disability, and walking speed in
patients with osteoarthritis (OA) of the knee. Participants
in this study were 106 individuals diagnosed as having OA of
at least one knee, who reported knee pain persisting for six
months or longer. Results suggest that pain catastrophizing
explained a significant proportion (all Ps < or = 0.05) of
variance in measures of pain (partial r(2) [pr(2)] = 0.10),
psychological disability (pr(2) = 0.20), physical disability
(pr(2) = 0.11), and gait velocity at normal (pr(2) = 0.04),
fast (pr(2) = 0.04), and intermediate speeds (pr(2) = 0.04).
Pain-related fear explained a significant proportion of the
variance in measures of psychological disability (pr(2) =
0.07) and walking at a fast speed (pr(2) = 0.05). Pain
cognitions, particularly pain catastrophizing, appear to be
important variables in understanding pain, disability, and
walking at normal, fast, and intermediate speeds in knee OA
patients. Clinicians interested in understanding variations
in pain and disability in this population may benefit by
expanding the focus of their inquiries beyond traditional
medical and demographic variables to include an assessment
of pain catastrophizing and pain-related
fear.},
Language = {eng},
Doi = {10.1016/j.jpainsymman.2008.05.009},
Key = {fds241099}
}
@article{fds241082,
Author = {Sims, EL and Carland, JM and Keefe, FJ and Kraus, VB and Guilak, F and Schmitt, D},
Title = {Sex differences in biomechanics associated with knee
osteoarthritis.},
Journal = {J Women Aging},
Volume = {21},
Number = {3},
Pages = {159-170},
Year = {2009},
ISSN = {1540-7322},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20183142},
Keywords = {Adult • Aged • Biomechanics • Female •
Humans • Imaging, Three-Dimensional • Male •
Middle Aged • Osteoarthritis, Knee • Prevalence
• Severity of Illness Index • Sex Distribution
• epidemiology* • physiopathology*},
Abstract = {Osteoarthritis of the knee is seen more frequently in
females than males. However, few studies have examined the
interplay of gender, gait mechanics, pain, and disability in
persons with osteoarthritis. This study examines the
influence of anthropometrics, radiographic disease severity,
pain, and disability on gender differences in gait mechanics
in patients with knee osteoarthritis. Gait mechanics for 26
men and 30 women were collected using 3-D kinematics and
kinetics. Women had a significantly lower knee adduction
moment than men and a significantly higher stride frequency.
Within female subjects, variations in gait mechanics were
primarily explained by weight, BMI, pain, and disability. In
males, variations in gait mechanics were primarily explained
by age and disability.},
Language = {eng},
Doi = {10.1080/08952840903054856},
Key = {fds241082}
}
@article{fds241097,
Author = {Pells, JJ and Shelby, RA and Keefe, FJ and Dixon, KE and Blumenthal, JA and LaCaille, L and Tucker, JM and Schmitt, D and Caldwell, DS and Kraus,
VB},
Title = {Arthritis self-efficacy and self-efficacy for resisting
eating: relationships to pain, disability, and eating
behavior in overweight and obese individuals with
osteoarthritic knee pain.},
Journal = {Pain},
Volume = {136},
Number = {3},
Pages = {340-347},
Year = {2008},
Month = {June},
ISSN = {1872-6623},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17764844},
Keywords = {Arthralgia • Comorbidity • Disability Evaluation
• Employment • Feeding Behavior* • Female
• Humans • Male • Middle Aged • North
Carolina • Obesity • Osteoarthritis, Knee •
Overweight • Prevalence • Prognosis • Risk
Assessment • Self Efficacy* • epidemiology •
epidemiology* • methods* • prevention & control
• statistics & numerical data},
Abstract = {This study examined arthritis self-efficacy and
self-efficacy for resisting eating as predictors of pain,
disability, and eating behaviors in overweight or obese
patients with osteoarthritis (OA) of the knee. Patients
(N=174) with a body mass index between 25 and 42 completed
measures of arthritis-related self-efficacy, weight-related
self-efficacy, pain, physical disability, psychological
disability, overeating, and demographic and medical
information. Hierarchical linear regression analyses were
conducted to examine whether arthritis self-efficacy
(efficacy for pain control, physical function, and other
symptoms) and self-efficacy for resisting eating accounted
for significant variance in pain, disability, and eating
behaviors after controlling for demographic and medical
characteristics. Analyses also tested whether the
contributions of self-efficacy were domain specific. Results
showed that self-efficacy for pain accounted for 14% (p=.01)
of the variance in pain, compared to only 3% accounted for
by self-efficacy for physical function and other symptoms.
Self-efficacy for physical function accounted for 10%
(p=.001) of the variance in physical disability, while
self-efficacy for pain and other symptoms accounted for 3%.
Self-efficacy for other (emotional) symptoms and resisting
eating accounted for 21% (p<.05) of the variance in
psychological disability, while self-efficacy for pain
control and physical function were not significant
predictors. Self-efficacy for resisting eating accounted for
28% (p=.001) of the variance in eating behaviors. Findings
indicate that self-efficacy is important in understanding
pain and behavioral adjustment in overweight or obese OA
patients. Moreover, the contributions of self-efficacy were
domain specific. Interventions targeting both arthritis
self-efficacy and self-efficacy for resisting eating may be
helpful in this population.},
Language = {eng},
Doi = {10.1016/j.pain.2007.07.012},
Key = {fds241097}
}
@article{fds241098,
Author = {Hanna, JB and Schmitt, D and Griffin, TM},
Title = {The energetic cost of climbing in primates.},
Journal = {Science (New York, N.Y.)},
Volume = {320},
Number = {5878},
Pages = {898},
Year = {2008},
Month = {May},
ISSN = {0036-8075},
Keywords = {Animals • Biomechanics • Body Size • Body
Weight • Energy Metabolism* • Locomotion •
Lorisidae • Oxygen Consumption • Saimiri •
Strepsirhini • Walking • physiology*},
Abstract = {Primates are exceptional among mammals for their climbing
abilities and arboreal lifestyles. Here we show that small
primates (less than 0.5 kilogram) consume the same amount of
mass-specific energy (COTTOT) whether climbing or walking a
given distance. COTTOT decreases with increasing body size
for walking but does not change for climbing. This
divergence of COTTOT is likely due to fundamental
differences in the biomechanical determinants of the costs
of climbing versus walking. These results have important
implications for understanding the origins of primates,
suggesting that small early primates may have been able to
move into a novel arboreal niche without increasing
metabolic costs.},
Language = {eng},
Doi = {10.1126/science.1155504},
Key = {fds241098}
}
@article{fds241078,
Author = {Bishop, KL and Pai, AK and Schmitt, D},
Title = {Whole body mechanics of stealthy walking in
cats.},
Journal = {PloS one},
Volume = {3},
Number = {11},
Pages = {e3808},
Year = {2008},
Month = {January},
ISSN = {1932-6203},
url = {http://hdl.handle.net/10161/4508 Duke open access
repository},
Keywords = {Animals • Cats • Energy Metabolism • Gait
• Locomotion • Mechanics • Walking •
physiology*},
Abstract = {The metabolic cost associated with locomotion represents a
significant part of an animal's metabolic energy budget.
Therefore understanding the ways in which animals manage the
energy required for locomotion by controlling muscular
effort is critical to understanding limb design and the
evolution of locomotor behavior. The assumption that
energetic economy is the most important target of natural
selection underlies many analyses of steady animal
locomotion, leading to the prediction that animals will
choose gaits and postures that maximize energetic
efficiency. Many quadrupedal animals, particularly those
that specialize in long distance steady locomotion, do in
fact reduce the muscular contribution required for walking
by adopting pendulum-like center of mass movements that
facilitate exchange between kinetic energy (KE) and
potential energy (PE). However, animals that are not
specialized for long distance steady locomotion may face a
more complex set of requirements, some of which may conflict
with the efficient exchange of mechanical energy. For
example, the "stealthy" walking style of cats may demand
slow movements performed with the center of mass close to
the ground. Force plate and video data show that domestic
cats (Felis catus, Linnaeus, 1758) have lower mechanical
energy recovery than mammals specialized for distance. A
strong negative correlation was found between mechanical
energy recovery and diagonality in the footfalls and there
was also a negative correlation between limb compression and
diagonality of footfalls such that more crouched postures
tended to have greater diagonality. These data show a
previously unrecognized mechanical relationship in which
crouched postures are associated with changes in footfall
pattern which are in turn related to reduced mechanical
energy recovery. Low energy recovery was not associated with
decreased vertical oscillations of the center of mass as
theoretically predicted, but rather with posture and
footfall pattern on the phase relationship between potential
and kinetic energy. An important implication of these
results is the possibility of a tradeoff between stealthy
walking and economy of locomotion. This potential tradeoff
highlights the complex and conflicting pressures that may
govern the locomotor choices that animals
make.},
Language = {eng},
Doi = {10.1371/journal.pone.0003808},
Key = {fds241078}
}
@article{fds241063,
Author = {Cartmill, M and Lemelin, P and Schmitt, D},
Title = {Primate gaits and primate origins},
Pages = {403-435},
Booktitle = {Primate Origins},
Publisher = {Springer US},
Editor = {M. Dagosto and M. Ravosa},
Year = {2007},
Month = {December},
Doi = {10.1007/978-0-387-33507-0_12},
Key = {fds241063}
}
@article{fds241064,
Author = {Lemelin, P and Schmitt, D},
Title = {Origins of grasping and locomotor adaptations in primates:
Comparative and experimental approaches using an opossum
model},
Pages = {329-380},
Publisher = {Springer US},
Year = {2007},
Month = {December},
Abstract = {Since the turn of the 20th century, most anthropologists
agreed on one fundamental notion: the origin and evolution
of the order Primates was closely tied with life in the
trees. This view is founded on the obvious observation that
the vast majority of extant primates live in the trees and
have colonized many different arboreal habitats. Smith
(1912) and Jones (1916) were among the first to relate some
of the unique anatomical and behavioral characteristics of
primates with arboreal life. Their views were promoted by
LeGros Clark (1959), but later challenged and refined by
Cartmill (1972, 1974a,b) who suggested that the
forward-facing eyes and grasping extremities of primates can
be interpreted as adaptations to cautious foraging for
insect prey on thin, flexible branches. At the same time,
Jenkins (1974: 112) suggested that "The adaptive innovation
of ancestral primates was therefore not the invasion of the
arboreal habitat, but their successful restriction to it."
However, there are several extant mammal species other than
primates that are restricted to an arboreal environment,
particularly in which thin and flexible branches abound. As
Cartmill (1972, 1974a,b) and Ramussen (1990) stressed, those
nonprimate mammals offer great potential in addressing the
problem of primate origins. The views of Jenkins and
Cartmill had a profound influence on the adaptive
explanations of the postcranial and locomotor features that
define primates as a group. Several primate postcranial and
locomotor characteristics, rare in other mammals, are now
being interpreted as evidence of an invasion and restriction
to a fine-branch, arboreal niche by the earliest primates.
For example, primates have prehensile hands and feet that
bear nails instead of sharp claws (Cartmill, 1970, 1972,
1974a,b, 1985; Jones, 1916, 1929; LeGros Clark, 1959;
Lemelin, 1996; Martin, 1968, 1986, 1990; Mivart, 1873;
Napier, 1961, 1993; Napier and Napier, 1967; Szalay and
Dagosto, 1988; Szalay et al., 1987) and relatively long
limbs (Alexander et al., 1979; Polk et al., 2000) with more
mobile joints, particularly in the forelimbs (Reynolds,
1985b). In addition to these postcranial features, most
primates share three locomotor characteristics that are
unusual or unique compared to other mammals (Larson, 1998).
During quadrupedal walking, primates are characterized by:
(a) an almost exclusive use of diagonal-sequence (DS)
walking gaits (i.e., each hind footfall is followed by the
contralateral fore footfall) (Cartmill et al., 2002;
Hildebrand, 1967, 1985; Rollinson and Martin, 1981; Vilensky
and Larson, 1989); (b) a protracted arm position at forelimb
touchdown (i.e., arm greater than 90 relative to horizontal
body axis) (Larson, 1998; Larson et al., 2000, 2001); (c)
relatively lower peak vertical substrate reaction forces
(Vpk) on the forelimbs compared to the hindlimbs (Demes et
al., 1994; Kimura et al., 1979; Reynolds, 1985b); and (d)
forelimb compliance (Larney and Larson 2004; Schmitt, 1998,
1999, 2003a,b; Schmitt and Hanna, 2004). What has been
lacking is a clear demonstration that mammals restricted to
a fine-branch environment possess similar postcranial and
locomotor characteristics that are functionally linked to
moving and foraging on thin arboreal supports. In this
chapter, we present the results of comparative and
experimental studies that test the relationship between the
presence of primate-like features and fine-branch
arborealism using ecological convergence between didelphid
marsupials and prosimian primates. Following a review of
various models of primates, we present morphometric and
behavioral data for opossums and primates that test
specifically the functional link between the presence of
more grasping, primate-like cheiridia and movement on thin
branches. In the second part, we report experimental results
that specifically test for the presence of three gait
characteristics typical of most primates in a fine-branch
arborealist, the woolly opossum (Caluromys philander). In
the last part of this chapter, we discuss how these data
accord with current theories of primate origins and assess
the relevance of an opossum model in inferring the locomotor
profile and ecological niche of the earliest primates. ©
Springer Science+Business Media, LLC 2007.},
Doi = {10.1007/978-0-387-33507-0_10},
Key = {fds241064}
}
@article{fds241090,
Author = {Hutchinson, D and Ho, V and Dodd, M and Dawson, HN and Zumwalt, AC and Schmitt, D and Colton, CA},
Title = {Quantitative measurement of postural sway in mouse models of
human neurodegenerative disease.},
Journal = {Neuroscience},
Volume = {148},
Number = {4},
Pages = {825-832},
Year = {2007},
Month = {September},
ISSN = {0306-4522},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17764851},
Keywords = {Age Factors • Amyloid beta-Protein Precursor •
Animals • Animals, Newborn • Behavior, Animal
• Biomechanics • Disease Models, Animal* •
Female • Harmaline • Humans • Male •
Mice • Mice, Inbred C57BL • Mice, Transgenic
• Monoamine Oxidase Inhibitors • Motor Activity
• Mutation • Neurodegenerative Diseases •
Nitric Oxide Synthase Type II • Postural Balance •
Posture • Tremor • adverse effects •
chemically induced • drug effects • genetics
• methods • physiology • physiology* •
physiopathology • physiopathology*},
Abstract = {Detection of motor dysfunction in genetic mouse models of
neurodegenerative disease requires reproducible,
standardized and sensitive behavioral assays. We have
utilized a center of pressure (CoP) assay in mice to
quantify postural sway produced by genetic mutations that
affect motor control centers of the brain. As a positive
control for postural instability, wild type mice were
injected with harmaline, a tremorigenic agent, and the
average areas of the 95% confidence ellipse, which measures
95% of the CoP trajectory values recorded in a single trial,
were measured. Ellipse area significantly increased in mice
treated with increasing doses of harmaline and returned to
control values after recovery. We also examined postural
sway in mice expressing mutations that mimic frontotemporal
dementia with Parkinsonism linked to chromosome 17 (FTDP-17)
(T-279, P301L or P301L-nitric oxide synthase 2 (NOS2)(-/-)
mice) and that demonstrate motor symptoms. These mice were
then compared with a mouse model of Alzheimer's disease
(APPSwDI mice) that demonstrates cognitive, but not motor
deficits. T-279 and P301L-NOS2(-/-) mice demonstrated a
significant increase in CoP ellipse area compared with
appropriate wild type control mice or to mice expressing the
P301L mutation alone. In contrast, postural instability was
significantly reduced in APPSwDI mice that have cognitive
deficits but do not have associated motor deficits. The CoP
assay provides a simple, sensitive and quantitative tool to
detect motor deficits resulting from postural abnormalities
in mice and may be useful in understanding the underlying
mechanisms of disease.},
Language = {eng},
Doi = {10.1016/j.neuroscience.2007.07.025},
Key = {fds241090}
}
@article{fds241101,
Author = {Cartmill, M and Lemelin, P and Schmitt, D},
Title = {Understanding the adaptive value of diagonal-sequence gaits
in primates: a comment on Shapiro and Raichlen,
2005.},
Journal = {American journal of physical anthropology},
Volume = {133},
Number = {2},
Pages = {822-825},
Year = {2007},
Month = {June},
ISSN = {0002-9483},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17427929},
Keywords = {Adaptation, Physiological* • Animals • Animals,
Newborn • Anthropology, Physical* • Biological
Evolution • Biomechanics • Gait • Primates
• Species Specificity • Walking • physiology
• physiology*},
Abstract = {This study examined arthritis self-efficacy and
self-efficacy for resisting eating as predictors of pain,
disability, and eating behaviors in overweight or obese
patients with osteoarthritis (OA) of the knee. Patients
(N=174) with a body mass index between 25 and 42 completed
measures of arthritis-related self-efficacy, weight-related
self-efficacy, pain, physical disability, psychological
disability, overeating, and demographic and medical
information. Hierarchical linear regression analyses were
conducted to examine whether arthritis self-efficacy
(efficacy for pain control, physical function, and other
symptoms) and self-efficacy for resisting eating accounted
for significant variance in pain, disability, and eating
behaviors after controlling for demographic and medical
characteristics. Analyses also tested whether the
contributions of self-efficacy were domain specific. Results
showed that self-efficacy for pain accounted for 14% (p=.01)
of the variance in pain, compared to only 3% accounted for
by self-efficacy for physical function and other symptoms.
Self-efficacy for physical function accounted for 10%
(p=.001) of the variance in physical disability, while
self-efficacy for pain and other symptoms accounted for 3%.
Self-efficacy for other (emotional) symptoms and resisting
eating accounted for 21% (p<.05) of the variance in
psychological disability, while self-efficacy for pain
control and physical function were not significant
predictors. Self-efficacy for resisting eating accounted for
28% (p=.001) of the variance in eating behaviors. Findings
indicate that self-efficacy is important in understanding
pain and behavioral adjustment in overweight or obese OA
patients. Moreover, the contributions of self-efficacy were
domain specific. Interventions targeting both arthritis
self-efficacy and self-efficacy for resisting eating may be
helpful in this population.},
Language = {eng},
Doi = {10.1002/ajpa.20589},
Key = {fds241101}
}
@article{fds241106,
Author = {Hanna, JB and Polk, JD and Schmitt, D},
Title = {Forelimb and hindlimb forces in walking and galloping
primates.},
Journal = {American journal of physical anthropology},
Volume = {130},
Number = {4},
Pages = {529-535},
Year = {2006},
Month = {August},
ISSN = {0002-9483},
Keywords = {Animals • Callithrix • Cercopithecus aethiops
• Cheirogaleidae • Erythrocebus patas •
Female • Forelimb • Gait • Hindlimb •
Kinetics • Locomotion • Macaca mulatta • Male
• Papio anubis • Primates • Videotape
Recording • Walking • Weight-Bearing •
physiology • physiology*},
Abstract = {One trait that distinguishes the walking gaits of most
primates from those of most mammalian nonprimates is the
distribution of weight between the forelimbs and hindlimbs.
Nonprimate mammals generally experience higher vertical peak
substrate reaction forces on the forelimb than on the
hindlimb. Primates, in contrast, generally experience higher
vertical peak substrate reaction forces on the hindlimb than
on the forelimb. It is currently unclear whether this
unusual pattern of force distribution characterizes other
primate gaits as well. The available kinetic data for
galloping primates are limited and present an ambiguous
picture about peak-force distribution among the limbs. The
present study investigates whether the pattern of
forelimb-to-hindlimb force distribution seen during walking
in primates is also displayed during galloping. Six species
of primates were video-recorded during walking and galloping
across a runway or horizontal pole instrumented with a
force-plate. The results show that while the force
differences between forelimb and hindlimb are not
significantly different from zero during galloping, the
pattern of force distribution is generally the same during
walking and galloping for most primate species. These
patterns and statistical results are similar to data
collected during walking on the ground. The pattern of limb
differentiation exhibited by primates during walking and
galloping stands in contrast to the pattern seen in most
nonprimate mammals, in which forelimb forces are
significantly higher. The data reported here and by Demes et
al. ([1994] J. Hum. Evol. 26:353-374) suggest that a
relative reduction of forelimb vertical peak forces is part
of an overall difference in locomotor mechanics between most
primates and most nonprimate mammals during both walking and
galloping.},
Language = {eng},
Doi = {10.1002/ajpa.20385},
Key = {fds241106}
}
@article{fds241107,
Author = {Schmitt, D and Cartmill, M and Griffin, TM and Hanna, JB and Lemelin,
P},
Title = {Adaptive value of ambling gaits in primates and other
mammals.},
Journal = {The Journal of experimental biology},
Volume = {209},
Number = {Pt 11},
Pages = {2042-2049},
Year = {2006},
Month = {June},
ISSN = {0022-0949},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16709907},
Keywords = {Adaptation, Physiological • Animals • Gait •
Locomotion • Models, Biological • Primates •
Species Specificity • anatomy & histology •
physiology • physiology*},
Abstract = {At speeds between the walk and the gallop, most mammals
trot. Primates almost never trot, and it has been claimed
that they transition directly from a walk to a gallop
without any distinctive mid-speed running gait. If true,
this would be another characteristic difference between the
locomotion of primates and that of most other quadrupedal
mammals. Presently, however, few data exist concerning the
actual presence or absence of intermediate-speed gaits (i.e.
gaits that are used between a walk and a gallop) in
primates. Video records of running in twelve primate species
reveal that, unlike most other mammals, all the primates
studied almost exclusively adopt an 'amble'--an
intermediate-speed running gait with no whole-body aerial
phase--rather than trot. Ambling is also common in elephants
and some horses, raising the question of why ambling is
preferred over trotting in these diverse groups of animals.
Mathematical analyses presented here show that ambling
ensures continuous contact of the body with the substrate
while dramatically reducing vertical oscillations of the
center of mass. This may explain why ambling appears to be
preferable to trotting for extremely large terrestrial
mammals such as elephants and for arboreal mammals like
primates that move on unstable branches. These findings
allow us to better understand the mechanics of these unusual
running gaits and shed new light on primate locomotor
evolution.},
Language = {eng},
Doi = {10.1242/jeb.02235},
Key = {fds241107}
}
@article{fds201335,
Author = {JB Hanna},
Title = {Kinematics of vertical climbing in lorises and Cheirogaleus
medius.},
Journal = {Journal of human evolution},
Volume = {50},
Number = {4},
Pages = {469-78},
Year = {2006},
Month = {April},
ISSN = {0047-2484},
Keywords = {Adaptation, Physiological • Animals • Biomechanics
• Cheirogaleidae • Hip • Leg •
Locomotion • Lorisidae • Species Specificity
• Thigh • classification • physiology •
physiology*},
Abstract = {The type of climbing exhibited by apes and atelines is
argued to have been important in the evolution of
specialized locomotion, such as suspensory locomotion and
bipedalism. However, little is known about the mechanics of
climbing in primates. Previous work shows that Asian apes
and atelines use larger joint excursions and longer strides
than African apes and the Japanese macaque, respectively.
This study expands knowledge of climbing mechanics by
providing the first quantitative kinematic data for vertical
climbing in four prosimian species: three lorisid species
(Loris tardigradus, Nycticebus coucang, and Nycticebus
pygmaeus) that share with apes and atelines morphological
traits arguably related to climbing, and a more generalized
quadruped, Cheirogaleus medius. Subjects were videotaped as
they climbed up a wooden pole. Kinematic values, such as
step length and limb excursions, were calculated and
compared between species. The results of this study show
that lorises, like Asian apes and spider monkeys, use
relatively larger joint excursions and longer steps than
does C. medius during climbing. These data lend further
support to the idea that some primate species (e.g.,
lorises, atelines, and apes) are more specialized
kinematically and morphologically for climbing than others.
Pilot data suggest that such kinematic differences in
climbing style across broad phylogenetic groups may relate
to the energetics of climbing. Such data may be important
for understanding the morphological and kinematic
adaptations to climbing exhibited by some
primates.},
Language = {eng},
Doi = {10.1016/j.jhevol.2005.12.001},
Key = {fds201335}
}
@article{fds241109,
Author = {Stevens, NJ and Schmitt, DO and Cole, TM and Chan,
L-K},
Title = {Technical note: out-of-plane angular correction based on a
trigonometric function for use in two-dimensional kinematic
studies.},
Journal = {American journal of physical anthropology},
Volume = {129},
Number = {3},
Pages = {399-402},
Year = {2006},
Month = {March},
ISSN = {0002-9483},
Keywords = {Biomechanics • Extremities* • Mathematics* •
Models, Theoretical* • methods*},
Abstract = {In two-dimensional (2D) kinematic studies, limb positions in
three-dimensional (3D) space observed in lateral view are
projected onto a 2D film plane. Elbow and knee-joint angles
that are less than 20 degrees out-of-plane of lateral-view
cameras generally exhibit very little measurable difference
from their 3D counterparts (Plagenhoef 1979 Environment,
Behavior, and Morphology; New York: Gustav Fisher, p.
95-118). However, when limb segment angles are more than 20
degrees out-of-plane, as is often the case in locomotor
studies of arboreal primates, elbow and knee angles can
appear significantly more extended than they actually are.
For this reason, a methodology is described that corrects 2D
out-of-plane angular estimates using a series of
trigonometric transformations.},
Language = {eng},
Doi = {10.1002/ajpa.20359},
Key = {fds241109}
}
@article{fds241108,
Author = {Zumwalt, AC and Hamrick, M and Schmitt, D},
Title = {Force plate for measuring the ground reaction forces in
small animal locomotion.},
Journal = {Journal of biomechanics},
Volume = {39},
Number = {15},
Pages = {2877-2881},
Year = {2006},
Month = {January},
ISSN = {0021-9290},
Keywords = {Animals • Biomechanics • Data Collection •
Equipment Design • Forelimb • Hindlimb •
Locomotion • Mice • Musculoskeletal Physiological
Phenomena • Physiology • Postural Balance •
instrumentation* • methods • physiology •
physiology*},
Abstract = {The importance of kinetic force plate studies of locomotion
in small animals has grown recently with the increasing use
of rodent models for studies of musculoskeletal diseases.
However, the force plates for use with animals much smaller
than a cat are difficult to design and use. Here we present
data on a commercially available small force plate that
accurately collects whole-body and, in a modified form,
single-limb ground reaction forces in mice. The method used
here is convenient, inexpensive, and readily adaptable for
use with a variety of small species.},
Language = {eng},
Doi = {10.1016/j.jbiomech.2005.10.006},
Key = {fds241108}
}
@article{fds241105,
Author = {Chi, K-J and Schmitt, D},
Title = {Mechanical energy and effective foot mass during impact
loading of walking and running.},
Journal = {Journal of biomechanics},
Volume = {38},
Number = {7},
Pages = {1387-1395},
Year = {2005},
Month = {July},
ISSN = {0021-9290},
Keywords = {Computer Simulation • Connective Tissue •
Elasticity • Energy Transfer • Foot • Gait
• Heel • Humans • Models, Biological* •
Posture • Running • Stress, Mechanical •
Walking • physiology • physiology*},
Abstract = {The human heel pad is considered an important structure for
attenuation of the transient force caused by heel-strike.
Although the mechanical properties of heel pads are
relatively well understood, the mechanical energy (Etot)
absorbed by the heel pad during the impact phase has never
been documented directly because data on the effective foot
mass (Meff) was previously unavailable during normal forward
locomotion. In this study, we use the impulse-momentum
method (IMM) for calculating Meff from moving subjects.
Mass-spring-damper models were developed to evaluate errors
and to examine the effects of pad property, upper body mass,
and effective leg spring on Meff. We simultaneously
collected ground reaction forces, pad deformation, and lower
limb kinematics during impact phase of barefoot walking,
running, and crouched walking. The latter was included to
examine the effect of knee angle on Meff. The magnitude of
Meff as a percentage of body mass (M(B)) varies with knee
angle at impact and significantly differs among gaits:
6.3%M(B) in walking, 5.3%M(B) in running, and 3.7%M(B) in
crouched walking. Our modeling results suggested that Meff
is insensitive to heel pad resilience and effective leg
stiffness. At the instant prior to heel strike, Etot ranges
from 0.24 to 3.99 J. The combination of video and forceplate
data used in this study allows analyses of Etot and Etot as
a function of heel-strike kinematics during normal
locomotion. Relationship between Meff and knee angle
provides insights into how changes in posture moderate
impact transients at different gaits.},
Language = {eng},
Doi = {10.1016/j.jbiomech.2004.06.020},
Key = {fds241105}
}
@article{fds241104,
Author = {Schmitt, D and Rose, MD and Turnquist, JE and Lemelin,
P},
Title = {Role of the prehensile tail during ateline locomotion:
experimental and osteological evidence.},
Journal = {American journal of physical anthropology},
Volume = {126},
Number = {4},
Pages = {435-446},
Year = {2005},
Month = {April},
ISSN = {0002-9483},
Keywords = {Animals • Anthropometry • Biomechanics • Bone
and Bones • Cebidae • Locomotion • Muscle,
Skeletal • Species Specificity • Tail •
anatomy & histology • anatomy & histology* •
physiology*},
Abstract = {The dynamic role of the prehensile tail of atelines during
locomotion is poorly understood. While some have viewed the
tail of Ateles simply as a safety mechanism, others have
suggested that the prehensile tail plays an active role by
adjusting pendulum length or controlling lateral sway during
bimanual suspensory locomotion. This study examines the bony
and muscular anatomy of the prehensile tail as well as the
kinematics of tail use during tail-assisted brachiation in
two primates, Ateles and Lagothrix. These two platyrrhines
differ in anatomy and in the frequency and kinematics of
suspensory locomotion. Lagothrix is stockier, has shorter
forelimbs, and spends more time traveling quadrupedally and
less time using bimanual suspensory locomotion than does
Ateles. In addition, previous studies showed that Ateles
exhibits greater hyperextension of the tail, uses its tail
to grip only on alternate handholds, and has a larger
abductor caudae medialis muscle compared to Lagothrix. In
order to investigate the relationship between anatomy and
behavior concerning the prehensile tail, osteological data
and kinematic data were collected for Ateles fusciceps and
Lagothrix lagothricha. The results demonstrate that Ateles
has more numerous and smaller caudal elements, particularly
in the proximal tail region. In addition, transverse
processes are relatively wider, and sacro-caudal
articulation is more acute in Ateles compared to Lagothrix.
These differences reflect the larger abductor muscle mass
and greater hyperextension in Ateles. In addition, Ateles
shows fewer side-to-side movements during tail-assisted
brachiation than does Lagothrix. These data support the
notion that the prehensile tail represents a critical
dynamic element in the tail-assisted brachiation of Ateles,
and may be useful in developing inferences concerning
behavior in fossil primates.},
Language = {eng},
Doi = {10.1002/ajpa.20075},
Key = {fds241104}
}
@article{fds53025,
Author = {CJ Vinyard and D Schmitt},
Title = {New technique for studying reaction forces during primate
behaviors on vertical substrates.},
Journal = {American journal of physical anthropology},
Volume = {125},
Number = {4},
Pages = {343-51},
Year = {2004},
Month = {December},
ISSN = {0002-9483},
Keywords = {Animals • Biomechanics • Biophysics •
Ergometry • Motor Activity • Primates •
instrumentation • instrumentation* • methods*
• physiology*},
Abstract = {Recording reaction forces from primates during behaviors on
vertical substrates, such as leaping, climbing, or biting
trees, typically requires the design and construction of
customized recording devices or mounting commercially
available force platforms in a vertical position. The
technical difficulties imposed by either option have
hindered in vivo research on the kinetics of primate
behaviors on vertical substrates. We describe a simple,
inexpensive apparatus for recording forces from primate
behaviors on vertical substrates. The apparatus includes an
instrumented beam fastened directly to a horizontal force
platform and a surrounding vertical substrate that does not
contact the instrumented beam or platform. The contact piece
at the end of the instrumented beam is positioned flush with
the noninstrumented vertical substrate, and reaction forces
elicited on this instrumented section are directed to the
force platform. Because most of the vertical substrate is
not instrumented, we can isolate and record forces from a
single limb or jaw during a behavior. Biewener and Full
([1992] Biomechanics Structures and Positions: A Practical
Approach; New York: Oxford University press, p. 45-73) gave
seven criteria to consider when designing a customized
force-recording device. Where appropriate, we tested if our
apparatus met their criteria. The apparatus accurately
records forces in three orthogonal directions, has low
cross-talk, maintains a high frequency response, exhibits a
linear response up to at least 200 Newtons, and displays a
uniform response to a given force across the instrumented
contact piece. Our design does not easily facilitate the
identification of the point of force application. Therefore,
joint moments cannot be easily calculated. This limitation,
however, does not affect the apparatus's ability to
accurately record the magnitude and direction of a force (as
shown by other tests). We developed this apparatus to
measure jaw forces during tree gouging in common marmosets
(Callithrix jacchus), but the general design can be readily
modified to study a variety of primate behaviors on vertical
substrates.},
Language = {eng},
Doi = {10.1002/ajpa.10395},
Key = {fds53025}
}
@article{fds241120,
Author = {Vinyard, CJ and Schmitt, D},
Title = {New technique for studying reaction forces during primate
behaviors on vertical substrates.},
Journal = {American journal of physical anthropology},
Volume = {125},
Number = {4},
Pages = {343-351},
Year = {2004},
Month = {December},
Abstract = {Recording reaction forces from primates during behaviors on
vertical substrates, such as leaping, climbing, or biting
trees, typically requires the design and construction of
customized recording devices or mounting commercially
available force platforms in a vertical position. The
technical difficulties imposed by either option have
hindered in vivo research on the kinetics of primate
behaviors on vertical substrates. We describe a simple,
inexpensive apparatus for recording forces from primate
behaviors on vertical substrates. The apparatus includes an
instrumented beam fastened directly to a horizontal force
platform and a surrounding vertical substrate that does not
contact the instrumented beam or platform. The contact piece
at the end of the instrumented beam is positioned flush with
the noninstrumented vertical substrate, and reaction forces
elicited on this instrumented section are directed to the
force platform. Because most of the vertical substrate is
not instrumented, we can isolate and record forces from a
single limb or jaw during a behavior. Biewener and Full
([1992] Biomechanics Structures and Positions: A Practical
Approach; New York: Oxford University press, p. 45-73) gave
seven criteria to consider when designing a customized
force-recording device. Where appropriate, we tested if our
apparatus met their criteria. The apparatus accurately
records forces in three orthogonal directions, has low
cross-talk, maintains a high frequency response, exhibits a
linear response up to at least 200 Newtons, and displays a
uniform response to a given force across the instrumented
contact piece. Our design does not easily facilitate the
identification of the point of force application. Therefore,
joint moments cannot be easily calculated. This limitation,
however, does not affect the apparatus's ability to
accurately record the magnitude and direction of a force (as
shown by other tests). We developed this apparatus to
measure jaw forces during tree gouging in common marmosets
(Callithrix jacchus), but the general design can be readily
modified to study a variety of primate behaviors on vertical
substrates.},
Doi = {10.1002/ajpa.10395},
Key = {fds241120}
}
@article{fds241103,
Author = {Schmitt, D and Lemelin, P},
Title = {Locomotor mechanics of the slender loris (Loris
tardigradus).},
Journal = {Journal of human evolution},
Volume = {47},
Number = {1-2},
Pages = {85-94},
Year = {2004},
Month = {July},
ISSN = {0047-2484},
Keywords = {Adaptation, Physiological • Animals •
Anthropology, Physical • Biomechanics • Female
• Lorisidae • Male • Posture • Trees
• Video Recording • Walking •
physiology*},
Abstract = {The quadrupedal walking gaits of most primates can be
distinguished from those of most other mammals by the
presence of diagonal-sequence (DS) footfall patterns and
higher peak vertical forces on the hindlimbs compared to the
forelimbs. The walking gait of the woolly opossum (Caluromys
philander), a highly arboreal marsupial, is also
characterized by diagonal-sequence footfalls and relatively
low peak forelimb forces. Among primates, three
species--Callithrix, Nycticebus, and Loris--have been
reported to frequently use lateral-sequence (LS) gaits and
experience relatively higher peak vertical forces on the
forelimbs. These patterns among primates and other mammals
suggest a strong association between footfall patterns and
force distribution on the limbs. However, current data for
lorises are limited and the frequency of DS vs. LS walking
gaits in Loris is still ambiguous. To test the hypothesis
that patterns of footfalls and force distribution on the
limbs are functionally linked, kinematic and kinetic data
were collected simultaneously for three adult slender
lorises (Loris tardigradus) walking on a 1.25 cm horizontal
pole. All subjects in this study consistently used
diagonal-sequence walking gaits and always had higher peak
vertical forces on their forelimbs relative to their
hindlimbs. These results call into question the hypothesis
that a functional link exists between the presence of
diagonal-sequence walking gaits and relatively higher peak
vertical forces on the hindlimbs. In addition, this study
tested models that explain patterns of force distribution
based on limb protraction angle or limb compliance. None of
the Loris subjects examined showed kinematic patterns that
would support current models proposing that weight
distribution can be adjusted by actively shifting weight
posteriorly or by changing limb stiffness. These data reveal
the complexity of adaptations to arboreal locomotion in
primates and indicate that diagonal-sequence walking gaits
and relatively low forelimb forces could have evolved
independently.},
Language = {eng},
Doi = {10.1016/j.jhevol.2004.05.006},
Key = {fds241103}
}
@article{fds241111,
Author = {Lemelin, P and Schmitt, D},
Title = {Seasonal variation in body mass and locomotor kinetics of
the fat-tailed dwarf lemur (Cheirogaleus
medius).},
Journal = {Journal of morphology},
Volume = {260},
Number = {1},
Pages = {65-71},
Year = {2004},
Month = {April},
Abstract = {The fat-tailed dwarf lemur (Cheirogaleus medius) is unusual
among primates in storing large amounts of fat
subcutaneously prior to hibernating during the winter
months. In doing so, it increases its body mass by more than
50%, with a substantial weight gain in the tail. This
seasonal increase in mass provides a unique natural
experiment to examine how changes in body mass affect
substrate reaction forces during locomotion. As body mass
increases, it is expected that the limbs of the fat-tailed
dwarf lemur will be subjected to greater peak vertical
substrate reaction forces during quadrupedal walking.
However, whether or not these peak substrate reaction forces
will increase proportionally across forelimbs and hindlimbs
as body mass increases is unknown. Substrate reaction forces
were collected on four adult C. medius walking quadrupedally
on a 28-mm pole attached to a force platform. Peak vertical
substrate reaction forces (Vpk) (N) were analyzed and
compared for a cross-sectional sample of different body
masses (180-300 g). Forelimb and hindlimb Vpk were
positively correlated with body mass, with hindlimb Vpk
always higher than forelimb Vpk. However, the rate at which
Vpk increased relative to body mass was higher for the
hindlimb than the forelimb. This disproportion in weight
distribution between the forelimbs and hindlimbs as body
mass increases appears to be linked to the accumulation of
fat in the tail. It is likely that storing fat in the tail
region may shift the center of mass more caudally, from a
more cranial position when the tail is thinner. Such a
caudal shift of the center of mass-either morphological or
dynamic-is believed to have played an important role in the
functional differentiation of the limbs and the evolution of
locomotor modes of several tetrapod groups, including
dinosaurs and primates.},
Doi = {10.1002/jmor.10214},
Key = {fds241111}
}
@article{fds241077,
Author = {Schmitt, D and Hanna, JB},
Title = {Substrate alters forelimb to hindlimb peak force ratios in
primates.},
Journal = {Journal of human evolution},
Volume = {46},
Number = {3},
Pages = {239-254},
Year = {2004},
Month = {March},
ISSN = {0047-2484},
Keywords = {Animals • Arm • Cheirogaleidae • Female
• Gait • Haplorhini • Leg • Male •
Primates • Weight-Bearing • physiology •
physiology*},
Abstract = {It is often claimed that the walking gaits of primates are
unusual because, unlike most other mammals, primates appear
to have higher vertical peak ground reaction forces on their
hindlimbs than on their forelimbs. Many researchers have
argued that this pattern of ground reaction force
distribution is part of a general adaptation to arboreal
locomotion. This argument is frequently used to support
models of primate locomotor evolution. Unfortunately, little
is known about the force distribution patterns of primates
walking on arboreal supports, nor do we completely
understand the mechanisms that regulate weight distribution
in primates. We collected vertical peak force data for seven
species of primates walking quadrupedally on instrumented
terrestrial and arboreal supports. Our results show that,
when walking on arboreal vs. terrestrial substrates,
primates generally have lower vertical peak forces on both
limbs but the difference is most extreme for the forelimb.
We found that force reduction occurs primarily by decreasing
forelimb and, to a lesser extent, hindlimb stiffness. As a
result, on arboreal supports, primates experience
significantly greater functional differentiation of the
forelimb and hindlimb than on the ground. These data support
long-standing theories that arboreal locomotion was a
critical factor in the differentiation of the forelimbs and
hindlimbs in primates. This change in functional role of the
forelimb may have played a critical role in the origin of
primates and facilitated the evolution of more specialized
locomotor behaviors.},
Language = {eng},
Doi = {10.1016/j.jhevol.2003.11.008},
Key = {fds241077}
}
@article{fds53028,
Author = {RF Kay and D Schmitt and CJ Vinyard and JM Perry and N Shigehara and M
Takai, N Egi},
Title = {The paleobiology of Amphipithecidae, South Asian late Eocene
primates.},
Journal = {Journal of human evolution},
Volume = {46},
Number = {1},
Pages = {3-25},
Year = {2004},
Month = {January},
ISSN = {0047-2484},
Keywords = {Animals • Anthropology, Physical* • Behavior,
Animal • Female • Fossils • Locomotion*
• Male • Orbit • Primates • Skull •
Tooth • anatomy & histology • anatomy &
histology*},
Abstract = {Analysis of the teeth, orbital, and gnathic regions of the
skull, and fragmentary postcranial bones provides evidence
for reconstructing a behavioral profile of Amphipithecidae:
Pondaungia, Amphipithecus, Myanmarpithecus (late middle
Eocene, Myanmar) and Siamopithecus (late Eocene, Thailand).
At 5-8 kg, Pondaungia, Amphipithecus, and Siamopithecus are
perhaps the largest known Eocene primates. The dental and
mandibular anatomy suggest that large-bodied amphipithecids
were hard-object feeders. The shape of the mandibular corpus
and stiffened symphysis suggest an ability to resist large
internal loads during chewing and to recruit significant
amounts of muscle forces from both the chewing and
non-chewing sides of the jaw so as to increase bite force
during mastication. The large spatulate upper central
incisor of Pondaungia and projecting robust canines of all
the larger amphipithecids suggest that incisal food
preparation was important. The molars of Siamopithecus,
Amphipithecus, and Pondaungia have weak shearing crests.
This, and the thick molar enamel found in Pondaungia,
suggests a diet of seeds and other hard objects low in
fiber. In contrast, Myanmarpithecus was smaller, about 1-2
kg; its cheek teeth suggest a frugivorous diet and do not
imply seed eating. Postcranial bones (humerus, ulna, and
calcaneus) of a single large amphipithecid individual from
Myanmar suggest an arboreal quadrupedal locomotor style like
that of howler monkeys or lorises. The humeral head is
rounded, proximally oriented, and the tuberosities are low
indicating an extremely mobile glenohumeral joint. The great
thickness of the midshaft cortical bone of the humerus
implies enhanced ability to resist bending and torsion, as
seen among slow moving primate quadrupeds. The elbow joint
exhibits articular features for enhanced stability in
habitually flexed positions, features also commonly found in
slow moving arboreal quadrupeds. The short distal load arm
of the calcaneus is consistent with, but not exclusive to,
slow, arboreal quadrupedalism, and suggests no reliance on
habitual leaping.},
Language = {eng},
Doi = {10.1016/j.jhevol.2003.11.008},
Key = {fds53028}
}
@article{fds241121,
Author = {Kay, RF and Schmitt, D and Vinyard, CJ and Perry, JMG and Shigehara, N and Takai, M and Egi, N},
Title = {The paleobiology of Amphipithecidae, South Asian late Eocene
primates.},
Journal = {Journal of human evolution},
Volume = {46},
Number = {1},
Pages = {3-25},
Year = {2004},
Month = {January},
ISSN = {0047-2484},
url = {http://www.ncbi.nlm.nih.gov/pubmed/14698683},
Abstract = {Analysis of the teeth, orbital, and gnathic regions of the
skull, and fragmentary postcranial bones provides evidence
for reconstructing a behavioral profile of Amphipithecidae:
Pondaungia, Amphipithecus, Myanmarpithecus (late middle
Eocene, Myanmar) and Siamopithecus (late Eocene, Thailand).
At 5-8 kg, Pondaungia, Amphipithecus, and Siamopithecus are
perhaps the largest known Eocene primates. The dental and
mandibular anatomy suggest that large-bodied amphipithecids
were hard-object feeders. The shape of the mandibular corpus
and stiffened symphysis suggest an ability to resist large
internal loads during chewing and to recruit significant
amounts of muscle forces from both the chewing and
non-chewing sides of the jaw so as to increase bite force
during mastication. The large spatulate upper central
incisor of Pondaungia and projecting robust canines of all
the larger amphipithecids suggest that incisal food
preparation was important. The molars of Siamopithecus,
Amphipithecus, and Pondaungia have weak shearing crests.
This, and the thick molar enamel found in Pondaungia,
suggests a diet of seeds and other hard objects low in
fiber. In contrast, Myanmarpithecus was smaller, about 1-2
kg; its cheek teeth suggest a frugivorous diet and do not
imply seed eating. Postcranial bones (humerus, ulna, and
calcaneus) of a single large amphipithecid individual from
Myanmar suggest an arboreal quadrupedal locomotor style like
that of howler monkeys or lorises. The humeral head is
rounded, proximally oriented, and the tuberosities are low
indicating an extremely mobile glenohumeral joint. The great
thickness of the midshaft cortical bone of the humerus
implies enhanced ability to resist bending and torsion, as
seen among slow moving primate quadrupeds. The elbow joint
exhibits articular features for enhanced stability in
habitually flexed positions, features also commonly found in
slow moving arboreal quadrupeds. The short distal load arm
of the calcaneus is consistent with, but not exclusive to,
slow, arboreal quadrupedalism, and suggests no reliance on
habitual leaping.},
Doi = {10.1016/j.jhevol.2003.09.009},
Key = {fds241121}
}
@article{fds241122,
Author = {Schmitt, D and Lemelin, P},
Title = {Locomotor mechanics of the slender loris.},
Journal = {Journal of Human Evolution},
Volume = {47},
Pages = {85-94},
Year = {2004},
Key = {fds241122}
}
@article{fds241123,
Author = {Schmitt, D and Hanna, J},
Title = {Substrate alters forelimb to hindlimb peak force ratios on
primates},
Journal = {Journal of Human Evolution},
Volume = {46},
Pages = {237-252},
Year = {2004},
Key = {fds241123}
}
@article{fds241124,
Author = {Lemelin, P and Schmitt, D},
Title = {easonal variation in body mass and locomotor dynamics of the
fat-tailed dwarf lemur (Cheirogaleus medius)},
Journal = {Journal of Morphology},
Volume = {260},
Pages = {65-71},
Year = {2004},
Key = {fds241124}
}
@article{fds241117,
Author = {Schmitt, D},
Title = {Substrate Size Primate Forelimb Mechanics: Implications for
Understanding the Evolution of Primate Locomotion},
Journal = {International Journal of Primatology},
Volume = {24},
Number = {5},
Pages = {1023-1036},
Year = {2003},
Month = {October},
ISSN = {0164-0291},
Abstract = {Did the anatomical and locomotor specializations of primates
evolve in response to requirements of locomotion and
foraging on thin branches? Laboratory studies of primates
and other mammals provide data suggesting that as substrate
size decreases primates will protract their arms to a
greater degree, lower the center of gravity by increasing
elbow flexion, and decrease forelimb substrate reaction
forces. I tested these hypotheses by calculating maximum arm
protraction, shoulder height, elbow flexion, and substrate
reaction forces during stance phase in 5 species of Old
World monkeys walking on a flat runway and raised poles of
varying diameters. As substrate size decreased most subjects
increased elbow flexion and lowered their shoulder height.
Three of the 5 species lowered peak substrate reaction
forces as substrate size decreased but, only 2 of the
species increased arm protraction as substrate size
decreased. These results reject the hypothesis that arm
protraction is a function of branch size, but provide
stronger support for the notion that branch size influences
elbow flexion, shoulder height, and peak substrate reaction
forces in some primates. The fact that biomechanical
expectations are met in some (but not all) cases and some
(but not all) species suggests that the topic is quite
complex and requires further study. Nonetheless, preliminary
data suggest that biomechanical accommodations to substrate
size may have played a role in the early differentiation of
primates from other mammals.},
Doi = {10.1023/A:1026224211797},
Key = {fds241117}
}
@article{fds241076,
Author = {Schmitt, D},
Title = {Evolutionary implications of the unusual walking mechanics
of the common marmoset (C. jacchus).},
Journal = {American journal of physical anthropology},
Volume = {122},
Number = {1},
Pages = {28-37},
Year = {2003},
Month = {September},
ISSN = {0002-9483},
Keywords = {Animals • Biological Evolution* • Biomechanics
• Callithrix • Gait • Male • Walking*
• anatomy & histology* • physiology},
Abstract = {Several features that appear to differentiate the walking
gaits of most primates from those of most other mammals (the
prevalence of diagonal-sequence footfalls, high degrees of
humeral protraction, and low forelimb vs. hindlimb peak
vertical forces) are believed to have evolved in response to
requirements of locomotion on thin arboreal supports by
early primates that had developed clawless grasping hands
and feet. This putative relationship between anatomy,
behavior, and ecology is tested here by examining gait
mechanics in the common marmoset (Callithrix jacchus), a
primate that has sharp claws and reduced pedal grasping, and
that spends much of its time clinging on large trunks.
Kinematic and kinetic data were collected on three male
Callithrix jacchus as they walked across a force platform
attached to the ground or to raised horizontal poles. The
vast majority of all walking gaits were lateral-sequence.
For all steps, the humerus was retracted (<90 degrees
relative to a horizontal axis) or held in a neutral (90
degrees ) position at forelimb touchdown. Peak vertical
forces on the forelimb were always higher than those on the
hindlimb. These three features of the walking gaits of C.
jacchus separate it from any other primate studied
(including other callitrichids). The walking gaits of C.
jacchus are mechanically more similar to those of small,
nonprimate mammals. The results of this study support
previous models that suggest that the unusual suite of
features that typify the walking gaits of most primates are
adaptations to the requirements of locomotion on thin
arboreal supports. These data, along with data from other
primates and marsupials, suggest that primate postcranial
and locomotor characteristics are part of a basal adaptation
for walking on thin branches.},
Language = {eng},
Doi = {10.1002/ajpa.10214},
Key = {fds241076}
}
@article{fds241118,
Author = {Lemelin, P and Schmitt, D and Cartmill, M},
Title = {Footfall patterns and interlimb co-ordination in opossums
(Family Didelphidae): Evidence for the evolution of
diagonal-sequence walking gaits in primates},
Journal = {Journal of Zoology},
Volume = {260},
Number = {4},
Pages = {423-429},
Publisher = {WILEY},
Year = {2003},
Month = {August},
Abstract = {Most primates typically use a diagonal-sequence footfall
pattern during walking. This footfall pattern, which is
unusual for mammals, is believed to have originated in
ancestral primates in association with the use of grasping
extremities for movement and foraging on thin, flexible
branches. This theory was tested by comparing gait
parameters between the grey short-tailed opossum Monodelphis
domestica and the woolly opossum Caluromys philander, two
didelphid marsupials that are strongly differentiated in
grasping morphology of the extremities and in their reliance
on foraging strategies involving thin branches. One hundred
and thirty gait cycles were analysed quantitatively from
videotapes of subjects moving quadrupedally on a runway and
on poles of different diameters (7 and 28 mm). Duty factor
(i.e. duration of the stance phase as a percentage of the
stride period) for the forelimb and hindlimb, as well as
diagonality (i.e. phase relationship between the forelimb
and hindlimb cycles), were calculated for each of these
symmetrical gait cycles. We found that the highly
terrestrial Monodelphis, like most other non-primate
mammals, relies primarily on lateral-sequence walking gaits
on both runway and poles, and has relatively higher forelimb
duty factors. Like primates, the highly arboreal Caluromys
uses primarily diagonal-sequence walking gaits on the runway
and pole, with relatively higher hindlimb duty factors and
diagonality. The fact that the woolly opossum, a marsupial
with primate-like feet that moves and forages mainly on thin
branches, uses primarily diagonal-sequence gaits when
walking supports the view that primate gaits evolved to meet
the demands of locomotion on narrow supports. This also
demonstrates the functional role of a grasping foot, in
association with relatively higher hindlimb duty factors,
protraction, and substrate reaction forces, in the
production of such walking gaits.},
Doi = {10.1017/S0952836903003856},
Key = {fds241118}
}
@article{fds53030,
Author = {D Schmitt},
Title = {Insights into the evolution of human bipedalism from
experimental studies of humans and other
primates.},
Journal = {The Journal of experimental biology},
Volume = {206},
Number = {Pt 9},
Pages = {1437-48},
Year = {2003},
Month = {May},
ISSN = {0022-0949},
Keywords = {Adaptation, Biological • Animals • Biological
Evolution* • Biomechanics • Gait • Humans
• Locomotion • Models, Biological •
physiology*},
Abstract = {An understanding of the evolution of human bipedalism can
provide valuable insights into the biomechanical and
physiological characteristics of locomotion in modern
humans. The walking gaits of humans, other bipeds and most
quadrupedal mammals can best be described by using an
inverted-pendulum model, in which there is minimal change in
flexion of the limb joints during stance phase. As a result,
it seems logical that the evolution of bipedalism in humans
involved a simple transition from a relatively stiff-legged
quadrupedalism in a terrestrial ancestor to relatively
stiff-legged bipedalism in early humans. However,
experimental studies of locomotion in humans and nonhuman
primates have shown that the evolution of bipedalism
involved a much more complex series of transitions,
originating with a relatively compliant form of
quadrupedalism. These studies show that relatively compliant
walking gaits allow primates to achieve fast walking speeds
using long strides, low stride frequencies, relatively low
peak vertical forces, and relatively high impact shock
attenuation ratios. A relatively compliant, ape-like bipedal
walking style is consistent with the anatomy of early
hominids and may have been an effective gait for a small
biped with relatively small and less stabilized joints,
which had not yet completely forsaken arboreal locomotion.
Laboratory-based studies of primates also suggest that human
bipedalism arose not from a terrestrial ancestor but rather
from a climbing, arboreal forerunner. Experimental data, in
conjunction with anatomical data on early human ancestors,
show clearly that a relatively stiff modern human gait and
associated physiological and anatomical adaptations are not
primitive retentions from a primate ancestor, but are
instead recently acquired characters of our
genus.},
Language = {eng},
Doi = {10.1002/ajpa.10214},
Key = {fds53030}
}
@article{fds241119,
Author = {Schmitt, D},
Title = {Insights into the evolution of human bipedalism from
experimental studies of humans and other
primates.},
Journal = {The Journal of experimental biology},
Volume = {206},
Number = {Pt 9},
Pages = {1437-1448},
Year = {2003},
Month = {May},
Abstract = {An understanding of the evolution of human bipedalism can
provide valuable insights into the biomechanical and
physiological characteristics of locomotion in modern
humans. The walking gaits of humans, other bipeds and most
quadrupedal mammals can best be described by using an
inverted-pendulum model, in which there is minimal change in
flexion of the limb joints during stance phase. As a result,
it seems logical that the evolution of bipedalism in humans
involved a simple transition from a relatively stiff-legged
quadrupedalism in a terrestrial ancestor to relatively
stiff-legged bipedalism in early humans. However,
experimental studies of locomotion in humans and nonhuman
primates have shown that the evolution of bipedalism
involved a much more complex series of transitions,
originating with a relatively compliant form of
quadrupedalism. These studies show that relatively compliant
walking gaits allow primates to achieve fast walking speeds
using long strides, low stride frequencies, relatively low
peak vertical forces, and relatively high impact shock
attenuation ratios. A relatively compliant, ape-like bipedal
walking style is consistent with the anatomy of early
hominids and may have been an effective gait for a small
biped with relatively small and less stabilized joints,
which had not yet completely forsaken arboreal locomotion.
Laboratory-based studies of primates also suggest that human
bipedalism arose not from a terrestrial ancestor but rather
from a climbing, arboreal forerunner. Experimental data, in
conjunction with anatomical data on early human ancestors,
show clearly that a relatively stiff modern human gait and
associated physiological and anatomical adaptations are not
primitive retentions from a primate ancestor, but are
instead recently acquired characters of our
genus.},
Doi = {10.1242/jeb.00279},
Key = {fds241119}
}
@article{fds241075,
Author = {Schmitt, D},
Title = {Mediolateral reaction forces and forelimb anatomy in
quadrupedal primates: implications for interpreting
locomotor behavior in fossil primates.},
Journal = {Journal of human evolution},
Volume = {44},
Number = {1},
Pages = {47-58},
Year = {2003},
Month = {January},
ISSN = {0047-2484},
Keywords = {Animals • Arm • Biomechanics • Elbow •
Fossils* • Haplorhini • Locomotion • Motor
Activity • Posture • anatomy & histology* •
physiology • physiology*},
Abstract = {The forelimb joints of terrestrial primate quadrupeds appear
better able to resist mediolateral (ML) shear forces than
those of arboreal quadrupedal monkeys. These differences in
forelimb morphology have been used extensively to infer
locomotor behavior in extinct primate quadrupeds. However,
the nature of ML substrate reaction forces (SRF) during
arboreal and terrestrial quadrupedalism in primates is not
known. This study documents ML-SRF magnitude and orientation
and forelimb joint angles in six quadrupedal anthropoid
species walking across a force platform attached to
terrestrial (wooden runway) and arboreal supports (raised
horizontal poles). On the ground all subjects applied a
lateral force in more than 50% of the steps collected. On
horizontal poles, in contrast, all subjects applied a
medially directed force to the substrate in more than 75% of
the steps collected. In addition, all subjects on arboreal
supports combined a lower magnitude peak ML-SRF with a
change in the timing of the ML-SRF peak force. As a result,
during quadrupedalism on the poles the overall SRF resultant
was relatively lower than it was on the runway. Most
subjects in this study adduct their humerus while on the
poles. The kinetic and kinematic variables combine to
minimize the tendency to collapse or translate forelimbs
joints in an ML plane in primarily arboreal quadrupedal
primates compared to primarily terrestrial quadrupedal ones.
These data allow for a more complete understanding of the
anatomy of the forelimb in terrestrial vs. arboreal
quadrupedal primates. A better understanding of the
mechanical basis of morphological differences allows greater
confidence in inferences concerning the locomotion of
extinct primate quadrupeds.},
Language = {eng},
Doi = {10.1016/s0047-2484(02)00165-3},
Key = {fds241075}
}
@article{fds304463,
Author = {Schmitt, D and Churchill, SE and Hylander, WL},
Title = {Experimental evidence concerning spear use in Neandertals
and early modern humans},
Journal = {Journal of Archaeological Science},
Volume = {30},
Number = {1},
Pages = {103-114},
Publisher = {Elsevier BV},
Year = {2003},
Month = {January},
Abstract = {Can a bimanual activity such as thrusting a spear during
hunting produce bilateral asymmetries in the strength of the
upper limbs? This question is important to arguments about
the predatory capabilities of Neandertals and early modern
humans. To address this question, we determined the
magnitude and direction of reaction forces on the upper
limbs during thrusting spear use. We collected lateral video
records of eight adults thrusting an instrumented aluminum
rod into a padded target. This "spear" was instrumented with
two sets of four strain gauges placed at two positions along
the shaft to register the force along the shaft and the
distribution of those forces relative to the two limbs. From
the gauge output and video we were able to calculate loads
experienced by the trailing limb (holding the proximal
spear) and the leading limb (holding the distal spear) as
well as approximate bending moments along the trailing limb.
The trailing limb provides a significantly greater portion
of the force during spear impact and when the spear is held
forcefully on the target. The loads on this limb at spear
impact are twice body weight and the bending moments on the
trailing humerus are large and appear to occur primarily in
the parasagittal plane. These data, in combination with
fossil humeral cross-sectional data and the lack of evidence
for throwing spears among Eurasian Neandertals, suggest that
previously documented humeral strength asymmetries in
Eurasian Neandertals and early Upper Palcolithic Modern
human males can be plausibly linked to spear thrusting. ©
2002 Elsevier Science Ltd. All rights reserved.},
Doi = {10.1006/jasc.2001.0814},
Key = {fds304463}
}
@article{fds44918,
Author = {D. Schmitt},
Title = {Evolutionary implications of the unusual walking mechanics
of the common marmoset (Callithrix jacchus).},
Journal = {American Journal of Physical Anthropology},
Volume = {122},
Pages = {28-37},
Year = {2003},
Key = {fds44918}
}
@article{fds241114,
Author = {Cartmill, M and Lemelin, P and Schmitt, D},
Title = {Support polygons and symmetrical gaits in
mammals},
Journal = {Zoological Journal of the Linnean Society},
Volume = {136},
Number = {3},
Pages = {401-420},
Publisher = {Oxford University Press (OUP)},
Year = {2002},
Month = {November},
Abstract = {The symmetrical gaits of quadrupedal mammals are often
described in terms of two variables: duty factor (S = the
stance period of one foot, as a percentage of the gait
cycle) and diagonality (D = the percentage of the cycle
period by which the left hind footfall precedes the left
fore footfall). We show that support polygons are optimized
during walking (i.e. the percentage of the locomotor cycle
spent standing on only two feet is minimized) for: (1) the
diagonal-sequence, diagonal-couplets walks characteristic of
primates (50 < D < 75) when D = [hindlimb S]; (2)
lateral-sequence, lateral-couplets walks (0 < D < 25) when D
= [hindlimb S] - 50; (3) lateral-sequence, diagonal-couplets
walks (25 < D < 50) when D = 100 - [forelimb S]. To
determine whether animal behaviour is optimal in this sense,
we examined 346 symmetrical gait cycles in 45 mammal
species. Our empirical data show that mammalian locomotor
behaviour approximates the theoretical optima. We suggest
that diagonal-sequence walking may be adopted by primates as
a means of ensuring that a grasping hindfoot is placed in a
protracted position on a tested support at the moment when
the contralateral forefoot strikes down on an untested
support. © 2002 The Linnean Society of London.},
Doi = {10.1046/j.1096-3642.2002.00038.x},
Key = {fds241114}
}
@article{fds53033,
Author = {E Krakauer and P Lemelin and D Schmitt},
Title = {Hand and body position during locomotor behavior in the
aye-aye (Daubentonia madagascariensis).},
Journal = {American journal of primatology},
Volume = {57},
Number = {3},
Pages = {105-18},
Year = {2002},
Month = {July},
ISSN = {0275-2565},
Keywords = {Animals • Biomechanics • Female • Hand •
Hand Injuries • Locomotion* • Male • Posture
• Strepsirhini* • Stress, Mechanical • Trees
• physiology* • veterinary},
Abstract = {Aye-ayes (Daubentonia madagascariensis) have unique hands
among primates, with extraordinarily long fingers in
relation to body size. These long digits may be vulnerable
to damage from forces during locomotion, particularly during
head-first descent-a locomotor mode that the aye-aye
utilizes frequently. Previous behavioral studies of aye-aye
locomotion reported that Daubentonia must curl its fingers
during horizontal quadrupedalism and/or descent to reduce
potential stresses on its long fingers. To test this
hypothesis, we examined hand and body position in three
captive adult aye-ayes while they walked quadrupedally on
horizontal and oblique branches. Substantial variation in
hand position was observed among individuals for each
substrate orientation. While hand postures with curled
fingers were preferred by one individual during descent,
they were not preferred by the other two individuals,
contrary to our expectations. Differences in body position
were more consistent among all three individuals. The angle
of the body relative to the substrate was significantly
reduced during descent (8.4 degrees ) compared to horizontal
locomotion (16.9 degrees ). These results suggest that
changes in body position, rather than hand position, may
help reduce stresses on the digits. A biomechanical model is
proposed that demonstrates how a reduction in the body angle
in relation to substrate may act to move the center of mass
more caudally. This mechanism of moderating loads by
altering body position, rather than hand position, may
represent an important functional aspect of arboreal
locomotion in aye-ayes and other primates.},
Language = {eng},
Doi = {10.1002/ajp.10038},
Key = {fds53033}
}
@article{fds241102,
Author = {Schmitt, D and Lemelin, P},
Title = {Origins of primate locomotion: gait mechanics of the woolly
opossum.},
Journal = {American journal of physical anthropology},
Volume = {118},
Number = {3},
Pages = {231-238},
Year = {2002},
Month = {July},
ISSN = {0002-9483},
Keywords = {Animals • Anthropology, Physical • Biomechanics
• Gait* • Locomotion* • Opossums •
Primates • Species Specificity • anatomy &
histology • physiology*},
Abstract = {The locomotion of primates differs from that of other
mammals in three fundamental ways. During quadrupedal
walking, primates use diagonal sequence gaits, protract
their arms more at forelimb touchdown, and experience lower
vertical substrate reaction forces on their forelimbs
relative to their hindlimbs. It is widely held that the
unusual walking gaits of primates represent a basal
adaptation for movement on thin, flexible branches and
reflect a major change in the functional role of the
forelimb. However, little data on nonprimate arboreal
mammals exist to test this notion. To that end, we examined
the gait mechanics of the woolly opossum (Caluromys
philander), a marsupial convergent with small-bodied
prosimians in ecology, behavior, and morphology. Data on the
footfall sequence, relative arm protraction, and peak
vertical substrate reaction forces were obtained from
videotapes and force records for three adult woolly opossums
walking quadrupedally on a wooden runway and a thin pole.
For all steps recorded on both substrates, woolly opossums
always used diagonal sequence walking gaits, protracted
their arms beyond 90 degrees relative to horizontal body
axis, and experienced peak vertical substrate reaction
forces on forelimbs that were significantly lower than on
hindlimbs. The woolly opossum is the first nonprimate mammal
to show locomotor mechanics that are identical to those of
primates. This case of convergence between primates and a
committed fine-branch, arboreal marsupial strongly implies
that the earliest primates evolved gait specializations for
fine-branch locomotion, which reflect important changes in
forelimb function.},
Language = {eng},
Doi = {10.1002/ajpa.10048},
Key = {fds241102}
}
@article{fds241115,
Author = {Krakauer, E and Lemelin, P and Schmitt, D},
Title = {Hand and body position during locomotor behavior in the
aye-aye (Daubentonia madagascariensis).},
Journal = {American journal of primatology},
Volume = {57},
Number = {3},
Pages = {105-118},
Year = {2002},
Month = {July},
ISSN = {0275-2565},
Abstract = {Aye-ayes (Daubentonia madagascariensis) have unique hands
among primates, with extraordinarily long fingers in
relation to body size. These long digits may be vulnerable
to damage from forces during locomotion, particularly during
head-first descent-a locomotor mode that the aye-aye
utilizes frequently. Previous behavioral studies of aye-aye
locomotion reported that Daubentonia must curl its fingers
during horizontal quadrupedalism and/or descent to reduce
potential stresses on its long fingers. To test this
hypothesis, we examined hand and body position in three
captive adult aye-ayes while they walked quadrupedally on
horizontal and oblique branches. Substantial variation in
hand position was observed among individuals for each
substrate orientation. While hand postures with curled
fingers were preferred by one individual during descent,
they were not preferred by the other two individuals,
contrary to our expectations. Differences in body position
were more consistent among all three individuals. The angle
of the body relative to the substrate was significantly
reduced during descent (8.4 degrees ) compared to horizontal
locomotion (16.9 degrees ). These results suggest that
changes in body position, rather than hand position, may
help reduce stresses on the digits. A biomechanical model is
proposed that demonstrates how a reduction in the body angle
in relation to substrate may act to move the center of mass
more caudally. This mechanism of moderating loads by
altering body position, rather than hand position, may
represent an important functional aspect of arboreal
locomotion in aye-ayes and other primates.},
Doi = {10.1002/ajp.10038},
Key = {fds241115}
}
@article{fds241116,
Author = {Schmitt, D and Churchill, SE and Hylander, WL},
Title = {Experimental evidence concerning spear use in Neandertals
and early modern humans.},
Journal = {Journal of Archaeological Sciences},
Volume = {30},
Number = {1},
Pages = {101-112},
Year = {2002},
Abstract = {Can a bimanual activity such as thrusting a spear during
hunting produce bilateral asymmetries in the strength of the
upper limbs? This question is important to arguments about
the predatory capabilities of Neandertals and early modern
humans. To address this question, we determined the
magnitude and direction of reaction forces on the upper
limbs during thrusting spear use. We collected lateral video
records of eight adults thrusting an instrumented aluminum
rod into a padded target. This "spear" was instrumented with
two sets of four strain gauges placed at two positions along
the shaft to register the force along the shaft and the
distribution of those forces relative to the two limbs. From
the gauge output and video we were able to calculate loads
experienced by the trailing limb (holding the proximal
spear) and the leading limb (holding the distal spear) as
well as approximate bending moments along the trailing limb.
The trailing limb provides a significantly greater portion
of the force during spear impact and when the spear is held
forcefully on the target. The loads on this limb at spear
impact are twice body weight and the bending moments on the
trailing humerus are large and appear to occur primarily in
the parasagittal plane. These data, in combination with
fossil humeral cross-sectional data and the lack of evidence
for throwing spears among Eurasian Neandertals, suggest that
previously documented humeral strength asymmetries in
Eurasian Neandertals and early Upper Palcolithic Modern
human males can be plausibly linked to spear thrusting. ©
2002 Elsevier Science Ltd. All rights reserved.},
Doi = {10.1006/jasc.2001.0814},
Key = {fds241116}
}
@article{fds241113,
Author = {Larson, SG and Schmitt, D and Lemelin, P and Hamrick,
M},
Title = {Limb excursion during quadrupedal walking: How do primates
compare to other mammals?},
Journal = {Journal of Zoology},
Volume = {255},
Number = {3},
Pages = {353-365},
Publisher = {WILEY},
Year = {2001},
Month = {November},
ISSN = {0952-8369},
Abstract = {Primate quadrupeds are said to use relatively large limb
excursions for mammals of their body size. Until recently,
this claim was based on a comparison of hindlimb excursion
data derived from small samples of primates and
non-primates. Using video recordings collected at zoos and
primate research centres, the present study documents this
contrast on much wider samples of quadrupedal mammals. The
results indicate that while on average hindlimb excursion is
relatively larger in quadrupedal primates, this contrast is
somewhat less dramatic than first reports suggested.
Comparisons between the data reported here and previously
collected forelimb excursion data reveal a surprising
asymmetry between the fore- and hind excursions for most
mammalian species. Most commonly, forelimb excursion exceeds
that of the hindlimb. We suggest that this is related to a
complementary asymmetry in limb length (forelimbs shorter
than hind) for the purpose of achieving equal step lengths
for both pairs of limbs. Relatively large hindlimb
excursions in primates have been related to a mechanism that
reduces stresses on the forelimbs and then recovers
mechanical energy during gait. We suggest that large
excursions of both the fore- and hindlimbs are linked to
other alterations in gait parameters, such as step length,
contact time, and limb compliance, that have been adopted in
quadrupedal primates to facilitate locomotion along slender
arboreal substrates.},
Doi = {10.1017/S0952836901001455},
Key = {fds241113}
}
@article{fds241112,
Author = {Larson, SG and Schmitt, D and Lemelin, P and Hamrick,
M},
Title = {Uniqueness of primate forelimb posture during quadrupedal
locomotion.},
Journal = {American journal of physical anthropology},
Volume = {112},
Number = {1},
Pages = {87-101},
Publisher = {WILEY},
Year = {2000},
Month = {May},
Abstract = {Among the characteristics that are thought to set primate
quadrupedal locomotion apart from that of nonprimate mammals
are a more protracted limb posture and larger limb angular
excursion. However, kinematic aspects of primate or
nonprimate quadrupedal locomotion have been documented in
only a handful of species, and more widely for the hind than
the forelimb. This study presents data on arm (humerus) and
forelimb posture during walking for 102 species of mammals,
including 53 nonhuman primates and 49 nonprimate mammals.
The results demonstrate that primates uniformly display a
more protracted arm and forelimb at hand touchdown of a step
than nearly all other mammals. Although primates tend to end
a step with a less retracted humerus, their total humeral or
forelimb angular excursion exceeds that of other mammals. It
is suggested that these features are components of
functional adaptations to locomotion in an arboreal habitat,
using clawless, grasping extremities.},
Doi = {10.1002/(sici)1096-8644(200005)112:1<87::aid-ajpa9>3.0.co;2-},
Key = {fds241112}
}
@article{fds241074,
Author = {Schmitt, D},
Title = {Compliant walking in primates},
Journal = {Journal of Zoology},
Volume = {248},
Number = {2},
Pages = {149-160},
Publisher = {WILEY},
Year = {1999},
Month = {June},
Abstract = {It is now well recognized that terrestrial mammals can
maintain equivalent bone stresses despite dramatic
differences in body size through the adoption of extended
limb positions during locomotion. However, this dynamic
solution is not available to all mammals. Medium- and
large-bodied arboreal mammals, such as anthropoid primates,
must maintain relatively gracile and mobile limbs in order
to manoeuvre in a discontinuous arboreal environment. But
they must also use flexed (i.e. crouched) limb positions in
order to maintain balance on arboreal substrates, thus
subjecting their gracile limbs to relatively high loads. To
determine how primates resolve this conflict between their
kinematics and their morphology, five species of Old World
monkeys were videotaped with lateral, frontal, and overhead
cameras while they walked at a range of natural speeds along
a runway and raised horizontal poles instrumented with a
force platform. Kinematic and kinetic data on the forelimb
show that during arboreal quadrupedalism, Old World monkeys
do crouch when travelling on arboreal supports compared to
the ground. Simultaneously, they lower vertical peak
reaction forces and thereby reduce and reorient the peak
resultant substrate reaction force, so that moment arms and
moments are roughly equivalent on poles and the ground. This
is accomplished through the adoption of a compliant walking
gait characterized by high degrees of forelimb protraction,
substantial elbow yield, low vertical oscillations of the
body, and long contact times. The use of a compliant walking
gait appears to be extremely rare among mammals and is most
likely related to an initial primate adaptation to
quadrupedal locomotion on terminal branches. This gait
represents a previously unrecognized dynamic postural
mechanism for maintenance of similar bone stresses and
safety factors in both arboreal and terrestrial
environments.},
Doi = {10.1017/S0952836999006020},
Key = {fds241074}
}
@article{fds241110,
Author = {Turnquist, JE and Schmitt, D and Rose, MD and Cant,
JG},
Title = {Pendular motion in the brachiation of captive Lagothrix and
Ateles.},
Journal = {American journal of primatology},
Volume = {48},
Number = {4},
Pages = {263-281},
Year = {1999},
Month = {January},
ISSN = {0275-2565},
Abstract = {Pendular motion during brachiation of captive Lagothrix
lagothricha lugens and Ateles fusciceps robustus was
analyzed to demonstrate similarities, and differences,
between these two closely related large bodied atelines.
This is the first captive study of the kinematics of
brachiation in Lagothrix. Videorecordings of one adult male
of each species were made in a specially designed cage
constructed at the DuMond Conservancy/Monkey Jungle, Miami,
FL. Java software (Jandel Scientific Inc., San Rafael, CA)
was used for frame-by-frame kinematic analysis of individual
strides/steps. Results demonstrate that the sequence of hand
and tail contacts differ significantly between the two
species with Lagothrix using a new tail hold with every hand
hold, while Ateles generally utilizes a new tail hold with
only every other hand hold. Stride length and stride
frequency, even after adjusting for limb length, also differ
significantly between the two species. Lagothrix brachiation
utilizes short, choppy strides with quick hand holds, while
Ateles uses long, fluid strides with longer hand holds.
During brachiation not only is Lagothrix's body
significantly less horizontal than that of Ateles but also,
within Ateles, there are significant differences between
steps depending on tail use. Because of the unique nature of
tail use in Ateles, many aspects of body positioning in
Lagothrix more closely resemble Ateles steps without a
simultaneous tail hold rather than those with one. Overall
pendulum length in Lagothrix is shorter than in Ateles. Tail
use in Ateles has a significant effect on maximum pendulum
length during a step. Although neither species achieves the
extreme pendulum effect and long period of free-flight of
hylobatids in fast ricochetal brachiation, in captivity both
consistently demonstrate effective brachiation with brief
periods of free-flight and pendular motion. Morphological
similarities between ateline brachiators and hylobatids are
fewer and less pronounced in Lagothrix than in Ateles. This
study demonstrates that Lagothrix brachiation is also less
hylobatid-like than that of Ateles.},
Doi = {10.1002/(sici)1098-2345(1999)48:4<263::aid-ajp2>3.0.co;2-9},
Key = {fds241110}
}
@article{fds241083,
Author = {Hamrick, MW and Churchill, SE and Schmitt, D and Hylander,
WL},
Title = {EMG of the human flexor pollicis longus muscle: implications
for the evolution of hominid tool use.},
Journal = {Journal of human evolution},
Volume = {34},
Number = {2},
Pages = {123-136},
Year = {1998},
Month = {February},
ISSN = {0047-2484},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9503091},
Abstract = {Modern humans possess a distinct and well-developed flexor
pollicis longus muscle, an extrinsic thumb flexor which is
"either rudimentary or absent" in great apes (Straus, 1942,
p. 228). Previous workers (e.g., Napier, 1962; Susman, 1988)
have related the origin of a well-developed flexor pollicis
longus muscle to the acquisition of precision grasping and
stone tool making capabilities in early hominids. The
proposed functional association between flexor pollicis
longus activity, precision grasping, and stone tool
manufacture has, however, never been tested experimentally.
This study uses electromyographic techniques (EMG) to
investigate the role of flexor pollicis longus during a
variety of tool making, tool using, and manipulatory
behaviors in order to determine the functional and
evolutionary significance of the human flexor pollicis
longus muscle. Our results indicate that flexor pollicis
longus is recruited during forceful tool using and stone
tool making behaviors, regardless of the power or precision
grip used to hold the tool. In particular, both stone tool
use and stone tool making employing three- and four-jaw
chuck precision grips elicit consistently high levels of FPL
activity. Flexor pollicis longus activity increases most
when resistance is increased to the thumb's volar pad during
these hammering, cutting, and knapping behaviors. In
contrast, we observed relatively low levels of flexor
pollicis longus activity during the fine manipulation of
food items, the making of slender wooden probes, and the use
of these probes as tools. The paleontological,
archaeological, and experimental data suggest that a
well-developed flexor pollicis longus muscle functioned
initially in the hominid lineage to stabilize the terminal
pollical phalanx against loads applied to the thumb's apical
pad during the frequent and forceful use of unmodified
stones as tools.},
Doi = {10.1006/jhev.1997.0177},
Key = {fds241083}
}
@article{fds241073,
Author = {Lemelin, P and Schmitt, D},
Title = {The relation between hand morphology and quadrupedalism in
primates},
Journal = {American Journal of Physical Anthropology},
Volume = {105},
Number = {2},
Pages = {185-197},
Year = {1998},
ISSN = {0002-9483},
Abstract = {Primate hands can be classified into two broad categories on
the basis of ray proportions and other features. Ectaxonic
hands are characterized by a longer fourth ray and are found
in most strepsirhines. Most haplorhines possess mesaxonic
hands which are characterized by a longer third ray.
Preuschoft et al. ([1993] in H. Preuschoft and D.J. Chivers
(eds.): Hands of Primates. Berlin: Springer-Verlag, pp.
21-30) proposed a biomechanical model which predicts that,
during quadrupedalism, a mesaxonic hand should be held in a
more neutral position with respect to the forearm, whereas
an ectaxonic hand should be more ulnarly deviated. The
relation between hand positioning and the mesaxony/ectaxony
categorization is investigated for 27 primate taxa.
Videotapes were recorded for each species walking
quadrupedally on arboreal supports. Several species were
also videotaped during ground quadrupedalism. The degree of
deviation of the hand relative to the substrate and the
grips utilized were quantified for 18 species from the
videotapes. Primates with mesaxonic hands use deviated hand
positions and grips, especially when walking quadrupedally
on small poles. Several species with ectaxonic hands use
neutral hand positions and grips when walking quadrupedally
on similar supports. Also, several primates, with either
ectaxonic or mesaxonic hands, display a combination of
deviated hand positions and grips when on arboreal
substrates and neutral hand positioning when on the ground.
The statistical results indicate that hand positioning
during quadrupedal walking is more variable than expected
based on the mesaxony/ectaxony classification. Furthermore,
radiographic data suggest that primates evolved at least two
different mechanisms of hand ulnar deviation.},
Doi = {10.1002/(SICI)1096-8644(199802)105:2<185::AID-AJPA6>3.0.CO;2},
Key = {fds241073}
}
@article{fds241072,
Author = {Schmitt, D},
Title = {Humeral Head Shape as an Indicator of Locomotor Behavior in
Extant Strepsirhines and Eocene Adapids},
Journal = {Folia Primatologica},
Volume = {67},
Number = {3},
Pages = {137-151},
Publisher = {S. Karger AG},
Year = {1997},
Month = {January},
ISSN = {0015-5713},
Keywords = {Analysis of Variance • Animals • Fossils* •
Humerus • Locomotion* • Multivariate Analysis
• Phylogeny* • Primates • Species Specificity
• Strepsirhini • anatomy & histology •
anatomy & histology* • classification •
physiology*},
Abstract = {Postcranial material from Notharctus, Smilodectes and
Cantius is abundant and well studied, but debate continues
over whether the locomotor repertoire of these animals
included a substantial component of vertical leaping. Here,
the shape of the humeral head of 11 genera of extant
strepsirhines, Notharctus, Smilodectes and Cantius was
quantified using serial mediolateral and proximodistal
contours. Univariate and multivariate analyses of these data
show that vertically leaping strepsirhines have a distally
relatively high narrow humeral head compared to arboreal
quadrupeds and it places Notharctus and Smilodectes in a
group with Hapalemur griseus, while Cantius is grouped with
Eulemur macaco, suggesting that a quadrupedal form preceded
the appearance of vertical leaping.},
Language = {eng},
Doi = {10.1159/000157215},
Key = {fds241072}
}
@article{fds318215,
Author = {Schmitt, D},
Title = {Humeral head shape as an indicator of locomotor behavior in
extant strepsirhines and Eocene adapids.},
Journal = {Folia primatologica; international journal of
primatology},
Volume = {67},
Number = {3},
Pages = {137-151},
Year = {1996},
Month = {January},
Abstract = {Postcranial material from Notharctus, Smilodectes and
Cantius is abundant and well studied, but debate continues
over whether the locomotor repertoire of these animals
included a substantial component of vertical leaping. Here,
the shape of the humeral head of 11 genera of extant
strepsirhines, Notharctus, Smilodectes and Cantius was
quantified using serial mediolateral and proximodistal
contours. Univariate and multivariate analyses of these data
show that vertically leaping strepsirhines have a distally
relatively high narrow humeral head compared to arboreal
quadrupeds and it places Notharctus and Smilodectes in a
group with Hapalemur griseus, while Cantius is grouped with
Eulemur macaco, suggesting that a quadrupedal form preceded
the appearance of vertical leaping.},
Doi = {10.1159/000157215},
Key = {fds318215}
}
@article{fds241070,
Author = {Schmitt, D and Larson, SG},
Title = {Heel contact as a function of substrate type and speed in
primates.},
Journal = {American journal of physical anthropology},
Volume = {96},
Number = {1},
Pages = {39-50},
Year = {1995},
Month = {January},
ISSN = {0002-9483},
Abstract = {In this report we provide detailed data on the patterns and
frequency of heel contact with terrestrial and arboreal
supports in primates. These data can help resolve the
question of whether African apes and humans are uniquely
"plantigrade" (Gebo [1992] Am. J. Phys. Anthropol. 89:29-58;
Gebo [1993a] Am. J. Phys. Anthropol. 91:382-385; Gebo
[1993b] Postcranial Adaptation in Nonhuman Primates), or if
plantigrady is common in other primates (Meldrum [1993] Am.
J. Phys. Anthropol. 91:379-381). Using biplanar and
uniplanar videotapes, we recorded the frequency and timing
of heel contact for a variety of primates (32 species)
walking on the ground and on simulated arboreal supports at
a range of natural speeds. Our results indicate that Pongo
as well as the African apes exhibit a "heel-strike" at the
end of swing phase. Ateles and Hylobates make heel contact
on all supports shortly after mid-foot contact, although
spider monkeys do so only at slow or moderate speeds. Data
available from uniplanar videotapes suggest that this
pattern occurs in Alouatta and Lagothrix as well. No other
New or Old World monkey or prosimian in this study made heel
contact during quadrupedalism on any substrate. Thus, heel
contact occurs in all apes and atelines, but only the great
apes exhibit a heel-strike. We suggest that heel contact
with the substrate is a by-product of an active posterior
weight-shift mechanism involving highly protracted hindlimbs
at touchdown. Force plate studies indicate that this
mechanism is most extreme in arboreally adapted primate
quadrupeds walking on arboreal supports. Although heel
contact and heel-strike may have no evolutionary link, it is
possible that both patterns are the result of a similar
weight shift mechanism. Therefore, the regular occurrence of
heel contact in a variety of arboreal primates, and the
absence of a true biomechanical link between limb
elongation, heel contact, and terrestriality, calls into
question the claim that hominid foot posture was necessarily
derived from a quadrupedal terrestrial ancestor.},
Doi = {10.1002/ajpa.1330960105},
Key = {fds241070}
}
@article{fds330391,
Author = {Demes, B and Larson, SG and Stern, JT and Jungers, WL and Biknevicius,
AR and Schmitt, D},
Title = {The kinetics of primate quadrupedalism: "hindlimb drive"
reconsidered},
Journal = {Journal of Human Evolution},
Volume = {26},
Number = {5-6},
Pages = {353-374},
Publisher = {Elsevier BV},
Year = {1994},
Month = {May},
Abstract = {Since Kimura et al.'s (1979) analysis of ground reaction
forces during quadrupedal walking, primates are commonly
pictured as being "hindlimb driven" compared to "forelimb
driven" nonprimate mammals. Hindlimb dominance in primates
has subsequently been interpreted as a preadaptation to
human bipedalism. However, given its considerable influence,
surprisingly little data are available to support this
putative contrast in limb dominance. In this reconsideration
of locomotor kinetics in primates, we have collected force
plate data on two chimpanzees, one orangutan, two vervet
monkeys, and two cats for a range of gaits and speeds. The
peak vertical forces acting on the limbs as well as the
braking and propulsive impulses exerted by the limbs are
examined. Forces and impulses are highly variable and change
with speed, gait, and the differential use of asynchronously
or asymmetrically placed limbs. Peak vertical forces
increase with speed. The faster gaits (trot, gallop) have,
on the average, higher forces than the walk. However, there
is no major change in force magnitudes at gait transitions.
The mean vertical forces are higher on the hindlimbs than on
the forelimbs of the primates. This difference is most
pronounced in the suspensory orangutan and least pronounced
in the quadrupedal vervets. Cats, on the other hand,
generate higher forelimb than hindlimb vertical forces.
Although our results support the overall conclusion of
Kimura et al. (1979) that peak vertical forces are
relatively low on the primate forelimb, they also show some
variation most probably related to locomotor mode. In the
majority of primate cases, the major propulsive thrust is
also generated by the hindlimbs. However, in the galloping
vervets, the trailing limbs are propulsive and the leading
limbs braking, no matter whether these are forelimbs or
hindlimbs. A similar, although less pronounced, asymmetry
between trailing and leading limbs was observed in a
galloping chimpanzee. Not only are primates variable with
regard to the roles of the limbs in propulsion, they are
also not unique among mammals in being predominantly
hindlimb driven. Our cats, as well as all other nonprimate
mammals so far analysed, generate greater propulsive thrust
with their hindlimbs; i.e. they are also "hindlimb driven".
© 1994 Academic Press. All rights reserved.},
Doi = {10.1006/jhev.1994.1023},
Key = {fds330391}
}
@article{fds241069,
Author = {Schmitt, D},
Title = {Forelimb mechanics as a function of substrate type during
quadrupedalism in two anthropoid primates},
Journal = {Journal of Human Evolution},
Volume = {26},
Number = {5-6},
Pages = {441-457},
Publisher = {Elsevier BV},
Year = {1994},
Month = {January},
Abstract = {During the past century, many anthropologists have proposed
that hominoid orthograde locomotion arose in an arboreal
quadrupedal ancestor with highly mobile, low weight-bearing
forelimbs. However, no quantitative data comparing kinematic
and kinetic aspects of forelimb use during arboreal and
terrestrial quadrupedalism have been available to evaluate
such theories. In this preliminary study, a spider monkey
and a baboon were videotaped in three planes while walking
quadrupedally on an instrumented runway and a raised
instrumented horizontal pole. Forelimb angles and substrate
reaction force resultants were calculated for each animal on
each substrate. The quantitative data presented here support
previous models for the evolution of primate locomotion that
were based on theoretical biomechanics and qualitative or
anecdotal evidence. In addition, this study has revealed
several previously undocumented accommodations to "arboreal"
quadrupedal locomotion in these two primates. While walking
on the pole, compared to travel on the ground, (1) both
animals adopted a "crouched" forelimb posture, but only the
spider monkey abducted its arm and ulnar deviated its hand;
(2) both subjects have lower resultant forces on the
forelimb due to lower absolute force magnitudes and changes
in the timing of component peaks; and (3) both animals
reduce and reorient transverse forces. Similar
accommodations to arboreal travel by both subjects appear to
be mechanical requirements of arboreal locomotion. However,
differences may be due to morphological differences between
the subjects, or to their divergent phylogenetic history.
These results are used to explore potential explanations for
the morphological differences between arboreal and
terrestrial primate quadrupeds in terms of bone and joint
strain and to evaluate models of primate locomotor
evolution. © 1994 Academic Press. All rights
reserved.},
Doi = {10.1006/jhev.1994.1027},
Key = {fds241069}
}
@article{fds330392,
Author = {Schmitt, D and Larson, SG and Stern, JT},
Title = {Serratus ventralis function in vervet monkeys (Cercopithecus
aethiops): are primate quadrupeds unique?},
Journal = {Journal of Zoology},
Volume = {232},
Number = {2},
Pages = {215-230},
Publisher = {WILEY},
Year = {1994},
Month = {January},
Abstract = {The serratus ventralis in mammals is a fan‐shaped
scapulo‐thoracic muscle that is believed by most
morphologists both to support body weight and to rotate the
scapula during quadrupedal locomotion. Electromyographic
studies of this muscle in cats, dogs and opossums confirm
the dual supportive and rotatory roles of the serratus
ventralis. Although this muscle has been studied in several
primate species, the concentration on arboreal locomotion
has resulted in an inadequate data set to permit direct
comparisons to non‐primate terrestrial quadrupeds. In
order to provide a more comparable data set, we examined
cranial, mid‐ and caudal thoracic regions of the serratus
ventralis during terrestrial quadrupedalism in the vervet
monkey, Cereopithecus aethiops. Our results indicate that
the serratus ventralis does support the body during the
stance phase of quadrupedalism in this primate. However,
unlike several non‐primate mammals, it plays a relatively
insignificant rotatory role during swing phase. Copyright ©
1994, Wiley Blackwell. All rights reserved},
Doi = {10.1111/j.1469-7998.1994.tb01570.x},
Key = {fds330392}
}
%% Papers Presented/Symposia/Abstracts
@article{fds346143,
Author = {Wiktorowicz-Conroy, AM and Pickering, P and Schmitt, DO and Doube, M and Shefelbine, SJ and Hutchinson, JR},
Title = {The Scaling of Postural Mechanics in Felidae and
Artiodactyla},
Journal = {INTEGRATIVE AND COMPARATIVE BIOLOGY},
Volume = {51},
Pages = {E150-E150},
Publisher = {OXFORD UNIV PRESS INC},
Year = {2011},
Month = {March},
Key = {fds346143}
}