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

First published online March 14, 2008
Journal of Experimental Biology 211, 1148-1162 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.012419

This Article Figures Only Full Text 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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Moreno, C. A. Articles by Biewener, A. A. PubMed PubMed Citation Articles by Moreno, C. A. Articles by Biewener, A. A.

Variability in forelimb bone strains during non-steady locomotor activities in goats

Carlos A. Moreno^1,*, Russell P. Main² and Andrew A. Biewener¹

¹ Concord Field Station, Department of Organismic and Evolutionary Biology, Harvard University, 100 Old Causeway Road, Bedford, MA 01730, USA
² Sibley School of Mechanical and Aerospace Engineering, 222 Upson Hall, Cornell University, Ithaca, NY 14853, USA

^* Author for correspondence (e-mail: cmoreno{at}oeb.harvard.edu)

Accepted 4 February 2008

The purpose of this study was to investigate the effects of non-steady locomotor activities on load predictability in two goat forelimb bones and to explore the degree to which bone curvature influences load predictability. We measured in vivo bone strains in the radius and metacarpus of juvenile goats performing a variety of natural behaviors in an outdoor arena and compared these strain magnitudes and loading patterns with those measured during steady-state treadmill locomotion. We sought to test two hypotheses: our first hypothesis expects an increase in the variability of strain magnitude and pattern during outdoor non-steady behavior when compared to treadmill locomotion. Our second hypothesis was that the curved radius experiences higher peak strains but less variability during non-steady activities than the straighter metacarpus. We found that unsteady, outdoor locomotion generally caused more variable strain patterns (consistent with the first hypothesis), but not more variable strain magnitudes, than treadmill locomotion in both bones. During outdoor locomotion, higher magnitude strain events in the radius showed more constrained loading patterns than in the metacarpus (consistent with the second hypothesis). In addition to the radius experiencing significantly greater bending strains compared to the straighter metacarpus, these results support the idea of a trade-off between increased predictability of loading pattern and increased bending-induced strain. Strain magnitudes recorded during both outdoor and treadmill locomotion showed a lognormal frequency distribution, but the outdoor bone strain distributions had a greater range because they included high magnitude loading events that did not occur during steady treadmill locomotion.

Key words: bone strain, variability, curvature, non-steady locomotion, skeletal mechanics, goat