Limb length and locomotor biomechanics in the genus Homo: An experimental study
Article first published online: 13 JUN 2007
Copyright © 2007 Wiley-Liss, Inc.
American Journal of Physical Anthropology
Volume 134, Issue 1, pages 106–116, September 2007
How to Cite
Gruss, L. T. (2007), Limb length and locomotor biomechanics in the genus Homo: An experimental study. Am. J. Phys. Anthropol., 134: 106–116. doi: 10.1002/ajpa.20642
- Issue published online: 24 JUL 2007
- Article first published online: 13 JUN 2007
- Manuscript Accepted: 26 MAR 2007
- Manuscript Received: 5 JUL 2006
- LSB Leakey Foundation
- NIH. Grant Number: 1PO1-AR-050245
- Department of Biological Anthropology and Anatomy, Duke University
- Pleistocene Homo
The striking variation in limb proportions within the genus Homo during the Pleistocene has important implications for understanding biomechanics in the later evolution of human bipedalism, because longer limbs and limb segments may increase bending moments about bones and joints. This research tested the hypothesis that long lower limbs and tibiae bring about increases in A-P bending forces on the lower limb during the stance phase of human walking. High-speed 3-D video data, force plates, and motion analysis software were used to analyze the walking gait of 27 modern human subjects. Limb length, as well as absolute and relative tibia length, were tested for associations with a number of kinetic and kinematic variables. Results show that individuals with longer limbs do incur greater bending moments along the lower limb during the first half of stance phase. During the second half of stance, individuals moderate bending moments through a complex of compensatory mechanisms, including keeping the knee in a more extended position. Neither absolute nor relative tibia length had any effect on the kinetic or kinematic variables tested. If these patterns apply to fossil Homo, groups with relatively long limbs (e.g. H. ergaster or early H. sapiens) may have experienced elevated bending forces along the lower limb during walking compared to those with relatively shorter limbs (e.g. the Neandertals). These increased forces could have led to greater reinforcement of joints and diaphyses. These results must be considered when formulating explanations for variation in limb morphology among Pleistocene hominins. Am J Phys Anthropol, 2007. © 2007 Wiley-Liss, Inc.