Beyond power limits: the kinetic energy capacity of skeletal muscle
File(s)
Published version
Author(s)
Labonte, David
Holt, Natalie C
Type
Journal Article
Abstract
Muscle is the universal agent of animal movement, and limits to muscle performance are therefore an integral aspect of animal behaviour, ecology and evolution. A mechanical perspective on movement makes it amenable to analysis from first principles, and so brings the seeming certitude of simple physical laws to the challenging comparative study of complex biological systems. Early contributions on movement biomechanics considered muscle energy output to be limited by muscle work capacity, Wmax; triggered by seminal work in the late 1960s, it is now held broadly that a complete analysis of muscle energy output must also consider muscle power capacity, for no unit of work can be delivered in arbitrarily brief time. Here, we adopt a critical stance towards this paradigmatic notion of a power limit, and argue that the alternative constraint to muscle energy output is imposed instead by a characteristic kinetic energy capacity, Kmax, dictated by the maximum speed with which the actuating muscle can shorten. The two critical energies can now be directly compared, and define the physiological similarity index, Γ=Kmax/Wmax. It is the explanatory power of this comparison that lends weight to a shift in perspective from muscle power to kinetic energy capacity, as is argued through a series of illustrative examples. Γ emerges as an important dimensionless number in musculoskeletal dynamics, and sparks novel hypotheses on functional adaptations in musculoskeletal ‘design’ that depart from the parsimonious evolutionary null hypothesis of geometric similarity.
Date Issued
2024-11-01
Date Acceptance
2024-08-29
Citation
Journal of Experimental Biology, 2024, 227 (21)
ISSN
0022-0949
Publisher
The Company of Biologists
Journal / Book Title
Journal of Experimental Biology
Volume
227
Issue
21
Copyright Statement
©2024. Published by The Company of Biologists Ltd This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properlyattributed.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/39234652
PII: 362414
Subjects
Biology
BIOMECHANICS
DESIGN
Dimensional analysis
ENERGETICS
FORCE
Jumping
Life Sciences & Biomedicine
Life Sciences & Biomedicine - Other Topics
Muscle physiology
Musculoskeletal modelling
OUTPUT
PERFORMANCE
Scaling
Science & Technology
SPEED
TENDON
TERM POWER
TRADE-OFF
Zoology
Publication Status
Published
Coverage Spatial
England
Article Number
jeb247150
Date Publish Online
2024-10-18