Ground-reaction-force profiles of bipedal walking in bipedally trained Japanese monkeys.
ABSTRACT Ground-reaction-force (GRF) profiles of bipedal locomotion in bipedally trained Japanese macaques (performing monkeys) were analyzed in order to clarify the dynamic characteristics of their locomotion. Five trained and two ordinary monkeys participated in the experiment. They walked on a wooden walkway at a self-selected speed, and three components of the GRF vector were measured using a force platform. Our measurements reveal that trained monkeys exhibited vertical-GRF profiles that were single-peaked, similar to those of ordinary monkeys; they did not generate the double-peaked force curve that is seen in humans, despite their extensive training. However, in the trained monkeys, the peak appeared relatively earlier in the stance phase, and overall shape was more triangular than that of the more parabolic profile generated by ordinary monkeys. Comparisons of vertical fluctuation of the center of body mass calculated from the measured profiles suggest that this was larger in the trained monkeys, indicating that storage and release of potential energy actually took place in their bipedal walking. This energetic advantage seems limited, however, because efficient exchange of potential and kinetic energy during walking were not completely out of phase as in human walking. We suggest that anatomically restricted range of hip-joint motion impedes the inherently quadrupedal monkeys from generating humanlike bipedal locomotion, and that morphological rearrangement of the hip joint was an essential precondition for protohominids to acquire humanlike bipedalism.
SourceAvailable from: François Druelle[Show abstract] [Hide abstract]
ABSTRACT: Non-human primates are commonly used as comparative models to investigate the evolutionary origins of habitual bipedal walking. After almost a century of research in the field of behaviour and functional anatomy, the need for integrative analyses is being widely discussed. In that perspective, the purpose of this note is to report on the available literature on quantitative behavioural and experimental studies of bipedalism in catarrhines. Examples are given of their respective contributions to fundamental knowledge on bipedalism in non-human primates. We then introduce various prospects for integrative explorations with a view to developing evolutionary hypotheses and to improve existing fundamental knowledge through experimental studies of the bipedal walking function in its ecological and behavioural contexts.Bulletins et Memoires de la Societe d'Anthropologie de Paris 07/2014; 26(3-4). DOI:10.1007/s13219-014-0105-2
[Show abstract] [Hide abstract]
ABSTRACT: Center of mass (CoM) oscillations were documented for 81 bipedal walking strides of three chimpanzees. Full-stride ground reaction forces were recorded as well as kinematic data to synchronize force to gait events and to determine speed. Despite being a bent-hip, bent-knee (BHBK) gait, chimpanzee walking uses pendulum-like motion with vertical oscillations of the CoM that are similar in pattern and relative magnitude to those of humans. Maximum height is achieved during single support and minimum height during double support. The mediolateral oscillations of the CoM are more pronounced relative to stature than in human walking when compared at the same Froude speed. Despite the pendular nature of chimpanzee bipedalism, energy recoveries from exchanges of kinetic and potential energies are low on average and highly variable. This variability is probably related to the poor phasic coordination of energy fluctuations in these facultatively bipedal animals. The work on the CoM per unit mass and distance (mechanical cost of transport) is higher than that in humans, but lower than that in bipedally walking monkeys and gibbons. The pronounced side sway is not passive, but constitutes 10% of the total work of lifting and accelerating the CoM. CoM oscillations of bipedally walking chimpanzees are distinctly different from those of BHBK gait of humans with a flat trajectory, but this is often described as “chimpanzee-like” walking. Human BHBK gait is a poor model for chimpanzee bipedal walking and offers limited insights for reconstructing early hominin gait evolution. Am J Phys Anthropol, 2014. © 2014 Wiley Periodicals, Inc.American Journal of Physical Anthropology 03/2015; 156(3). DOI:10.1002/ajpa.22667 · 2.51 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: In human bipedal walking, temporal changes in the elevation angle of the thigh, shank and foot segments covary to form a regular loop within a single plane in three-dimensional space. In this study, we quantified the planar covariation of limb elevation angles during bipedal locomotion in common quails to test whether the degree of planarity and the orientation of the covariance plane differ between birds, humans and Japanese macaques as reported in published accounts. Five quails locomoted on a treadmill and were recorded by a lateral X-ray fluoroscopy. The elevation angle of the thigh, shank and foot segments relative to the vertical axis was calculated and compared with published data on human and macaque bipedal locomotion. Results showed that the planar covariation applied to quail bipedal locomotion and planarity was stronger in quails than in humans. The orientation of the covariation plane in quails differed from that in humans, and was more similar to the orientation of the covariation plane in macaques. Although human walking is characterized by vaulting mechanics of the body center of mass, quails and macaques utilize spring-like running mechanics even though the duty factor is >0.5. Therefore, differences in the stance leg mechanics between quails and humans may underlie the difference in the orientation of the covariation plane. The planar covariation of inter-segmental coordination has evolved independently in both avian and human locomotion, despite the different mechanical constraints.Journal of Experimental Biology 09/2014; DOI:10.1242/jeb.109355 · 3.00 Impact Factor