Table of Contents
Journal of Anthropology
Volume 2012 (2012), Article ID 340493, 9 pages
http://dx.doi.org/10.1155/2012/340493
Research Article

Size and Shape: Morphology's Impact on Human Speed and Mobility

1Department of Biology, Seattle Pacific University, Suite 205, 3307 3rd Avenue West, Seattle, WA 98119-1997, USA
2Department of Anthropology, University of Washington Seattle, WA 98195, USA

Received 27 March 2012; Revised 23 June 2012; Accepted 11 July 2012

Academic Editor: Benjamin Campbell

Copyright © 2012 Cara M. Wall-Scheffler. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

While human sexual dimorphism is generally expected to be the result of differential reproductive strategies, it has the potential to create differences in the energetics of locomotion and the speed at which each morph travels, particularly since people have been shown to choose walking speeds around their metabolic optimum. Here, people of varying sizes walked around a track at four self-selected speeds while their metabolic rate was collected, in order to test whether the size variation within a population could significantly affect the shape of the optimal walking curve. The data show that larger people have significantly faster optimal walking speeds, higher costs at their optimal speed, and a more acute optimal walking curve (thus an increased penalty for walking at suboptimal speeds). Bigger people who also have wider bitrochanteric breadths have lower metabolic costs at their minimum than bigger people with a more narrow bitrochanteric breadth. Finally, tibia length significantly positively predicts optimal walking speed. These results suggest sex-specific walking groups typical of living human populations may be the result of energy maximizing strategies. In addition, testable hypotheses of group strategies are put forth.