QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Steudel, K Search for Related Content PubMed Articles by Steudel, K

Journal of Experimental Biology, Vol 154, Issue 1 287-303, Copyright © 1990 by Company of Biologists

JOURNAL ARTICLES

The work and energetic cost of locomotion. II. Partitioning the cost of internal and external work within a species

K Steudel
Department of Zoology, University of Wisconsin-Madison 53706.

Previous studies have shown that large animals have systematically lower mass-specific costs of locomotion than do smaller animals, in spite of there being no demonstrable difference between them in the mass-specific mechanical work of locomotion. Larger animals are somehow much more efficient at converting metabolic energy to mechanical work. The present study analyzes how this decoupling of work and cost might occur. The experimental design employs limb-loaded and back-loaded dogs and allows the energetic cost of locomotion to be partitioned between that used to move the center of mass (external work) and that used to move the limbs relative to the center of mass (internal work). These costs were measured in three dogs moving at four speeds. Increases in the cost of external work with speed parallel increases in the amount of external work based on data from previous studies. However, increases in the cost of internal work with speed are much less (less than 50%) than the increase in internal work itself over the speeds examined. Furthermore, the cost of internal work increases linearly with speed, whereas internal work itself increases as a power function of speed. It is suggested that this decoupling results from an increase with speed in the extent to which the internal work of locomotion is powered by non-metabolic means, such as elastic strain energy and transfer of energy within and between body segments.

This article has been cited by other articles:

				F. E. Nelson and T. J. Roberts Task-dependent force sharing between muscle synergists during locomotion in turkeys J. Exp. Biol., April 15, 2008; 211(8): 1211 - 1220. [Abstract] [Full Text] [PDF]

				R. L. Marsh, D. J. Ellerby, H. T. Henry, and J. Rubenson The energetic costs of trunk and distal-limb loading during walking and running in guinea fowl Numida meleagris: I. Organismal metabolism and biomechanics J. Exp. Biol., June 1, 2006; 209(11): 2050 - 2063. [Abstract] [Full Text] [PDF]

				J. Doke, J. M. Donelan, and A. D. Kuo Mechanics and energetics of swinging the human leg J. Exp. Biol., February 1, 2005; 208(3): 439 - 445. [Abstract] [Full Text] [PDF]

				R. L. Marsh, D. J. Ellerby, J. A. Carr, H. T. Henry, and C. I. Buchanan Partitioning the Energetics of Walking and Running: Swinging the Limbs Is Expensive Science, January 2, 2004; 303(5654): 80 - 83. [Abstract] [Full Text] [PDF]