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Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power

The fastest land animals are of intermediate size. Cheetah, antelope, greyhounds and racehorses have been measured running much faster than reported for elephants or elephant shrews. Can this be attributed to scaling of physical demands and explicit physiological constraints to supply? Here, we desc...

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Detalles Bibliográficos
Autores principales: Usherwood, J. R., Gladman, N. W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655479/
https://www.ncbi.nlm.nih.gov/pubmed/33023380
http://dx.doi.org/10.1098/rsbl.2020.0579
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author Usherwood, J. R.
Gladman, N. W.
author_facet Usherwood, J. R.
Gladman, N. W.
author_sort Usherwood, J. R.
collection PubMed
description The fastest land animals are of intermediate size. Cheetah, antelope, greyhounds and racehorses have been measured running much faster than reported for elephants or elephant shrews. Can this be attributed to scaling of physical demands and explicit physiological constraints to supply? Here, we describe the scaling of mechanical work demand each stride, and the mechanical power demand each stance. Unlike muscle stress, strain and strain rate, these mechanical demands cannot be circumvented by changing the muscle gearing with minor adaptations in bone geometry or trivial adjustments to limb posture. Constraints to the capacity of muscle to supply work and power impose fundamental limitations to maximum speed. Given an upper limit to muscle work capacity each contraction, maximum speeds in big animals are constrained by the mechanical work demand each step. With an upper limit to instantaneous muscle power production, maximal speeds in small animals are limited by the high power demands during brief stance periods. The high maximum speed of the cheetah may therefore be attributed as much to its size as to its other anatomical and physiological adaptations.
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spelling pubmed-76554792020-11-12 Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power Usherwood, J. R. Gladman, N. W. Biol Lett Biomechanics The fastest land animals are of intermediate size. Cheetah, antelope, greyhounds and racehorses have been measured running much faster than reported for elephants or elephant shrews. Can this be attributed to scaling of physical demands and explicit physiological constraints to supply? Here, we describe the scaling of mechanical work demand each stride, and the mechanical power demand each stance. Unlike muscle stress, strain and strain rate, these mechanical demands cannot be circumvented by changing the muscle gearing with minor adaptations in bone geometry or trivial adjustments to limb posture. Constraints to the capacity of muscle to supply work and power impose fundamental limitations to maximum speed. Given an upper limit to muscle work capacity each contraction, maximum speeds in big animals are constrained by the mechanical work demand each step. With an upper limit to instantaneous muscle power production, maximal speeds in small animals are limited by the high power demands during brief stance periods. The high maximum speed of the cheetah may therefore be attributed as much to its size as to its other anatomical and physiological adaptations. The Royal Society 2020-10 2020-10-07 /pmc/articles/PMC7655479/ /pubmed/33023380 http://dx.doi.org/10.1098/rsbl.2020.0579 Text en © 2020 The Authors. http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/http://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Biomechanics
Usherwood, J. R.
Gladman, N. W.
Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power
title Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power
title_full Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power
title_fullStr Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power
title_full_unstemmed Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power
title_short Why are the fastest runners of intermediate size? Contrasting scaling of mechanical demands and muscle supply of work and power
title_sort why are the fastest runners of intermediate size? contrasting scaling of mechanical demands and muscle supply of work and power
topic Biomechanics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655479/
https://www.ncbi.nlm.nih.gov/pubmed/33023380
http://dx.doi.org/10.1098/rsbl.2020.0579
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