Whole body mechanics of stealthy walking in cats.

The metabolic cost associated with locomotion represents a significant part of an animal's metabolic energy budget. Therefore understanding the ways in which animals manage the energy required for locomotion by controlling muscular effort is critical to understanding limb design and the evoluti...

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Main Authors: Kristin L Bishop, Anita K Pai, Daniel Schmitt
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2008-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC2583958?pdf=render
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spelling doaj-fbc561451daa4ba38719e270be68ca3d2020-11-25T02:03:32ZengPublic Library of Science (PLoS)PLoS ONE1932-62032008-01-01311e380810.1371/journal.pone.0003808Whole body mechanics of stealthy walking in cats.Kristin L BishopAnita K PaiDaniel SchmittThe metabolic cost associated with locomotion represents a significant part of an animal's metabolic energy budget. Therefore understanding the ways in which animals manage the energy required for locomotion by controlling muscular effort is critical to understanding limb design and the evolution of locomotor behavior. The assumption that energetic economy is the most important target of natural selection underlies many analyses of steady animal locomotion, leading to the prediction that animals will choose gaits and postures that maximize energetic efficiency. Many quadrupedal animals, particularly those that specialize in long distance steady locomotion, do in fact reduce the muscular contribution required for walking by adopting pendulum-like center of mass movements that facilitate exchange between kinetic energy (KE) and potential energy (PE). However, animals that are not specialized for long distance steady locomotion may face a more complex set of requirements, some of which may conflict with the efficient exchange of mechanical energy. For example, the "stealthy" walking style of cats may demand slow movements performed with the center of mass close to the ground. Force plate and video data show that domestic cats (Felis catus, Linnaeus, 1758) have lower mechanical energy recovery than mammals specialized for distance. A strong negative correlation was found between mechanical energy recovery and diagonality in the footfalls and there was also a negative correlation between limb compression and diagonality of footfalls such that more crouched postures tended to have greater diagonality. These data show a previously unrecognized mechanical relationship in which crouched postures are associated with changes in footfall pattern which are in turn related to reduced mechanical energy recovery. Low energy recovery was not associated with decreased vertical oscillations of the center of mass as theoretically predicted, but rather with posture and footfall pattern on the phase relationship between potential and kinetic energy. An important implication of these results is the possibility of a tradeoff between stealthy walking and economy of locomotion. This potential tradeoff highlights the complex and conflicting pressures that may govern the locomotor choices that animals make.http://europepmc.org/articles/PMC2583958?pdf=render
collection DOAJ
language English
format Article
sources DOAJ
author Kristin L Bishop
Anita K Pai
Daniel Schmitt
spellingShingle Kristin L Bishop
Anita K Pai
Daniel Schmitt
Whole body mechanics of stealthy walking in cats.
PLoS ONE
author_facet Kristin L Bishop
Anita K Pai
Daniel Schmitt
author_sort Kristin L Bishop
title Whole body mechanics of stealthy walking in cats.
title_short Whole body mechanics of stealthy walking in cats.
title_full Whole body mechanics of stealthy walking in cats.
title_fullStr Whole body mechanics of stealthy walking in cats.
title_full_unstemmed Whole body mechanics of stealthy walking in cats.
title_sort whole body mechanics of stealthy walking in cats.
publisher Public Library of Science (PLoS)
series PLoS ONE
issn 1932-6203
publishDate 2008-01-01
description The metabolic cost associated with locomotion represents a significant part of an animal's metabolic energy budget. Therefore understanding the ways in which animals manage the energy required for locomotion by controlling muscular effort is critical to understanding limb design and the evolution of locomotor behavior. The assumption that energetic economy is the most important target of natural selection underlies many analyses of steady animal locomotion, leading to the prediction that animals will choose gaits and postures that maximize energetic efficiency. Many quadrupedal animals, particularly those that specialize in long distance steady locomotion, do in fact reduce the muscular contribution required for walking by adopting pendulum-like center of mass movements that facilitate exchange between kinetic energy (KE) and potential energy (PE). However, animals that are not specialized for long distance steady locomotion may face a more complex set of requirements, some of which may conflict with the efficient exchange of mechanical energy. For example, the "stealthy" walking style of cats may demand slow movements performed with the center of mass close to the ground. Force plate and video data show that domestic cats (Felis catus, Linnaeus, 1758) have lower mechanical energy recovery than mammals specialized for distance. A strong negative correlation was found between mechanical energy recovery and diagonality in the footfalls and there was also a negative correlation between limb compression and diagonality of footfalls such that more crouched postures tended to have greater diagonality. These data show a previously unrecognized mechanical relationship in which crouched postures are associated with changes in footfall pattern which are in turn related to reduced mechanical energy recovery. Low energy recovery was not associated with decreased vertical oscillations of the center of mass as theoretically predicted, but rather with posture and footfall pattern on the phase relationship between potential and kinetic energy. An important implication of these results is the possibility of a tradeoff between stealthy walking and economy of locomotion. This potential tradeoff highlights the complex and conflicting pressures that may govern the locomotor choices that animals make.
url http://europepmc.org/articles/PMC2583958?pdf=render
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