The effect of muscle ultrastructure on the force, displacement and work capacity of skeletal muscle
File(s)
Published version
Author(s)
Dhawale, Nihav
Labonte, David
Holt, Natalie C
Type
Journal Article
Abstract
Skeletal muscle powers animal movement through interactions between the contractile proteins, actin and myosin. Structural variation contributes greatly to the variation in mechanical performance observed across muscles. In vertebrates, gross structural variation occurs in the form of changes in the muscle cross-sectional area : fibre length ratio. This results in a trade-off between force and displacement capacity, leaving work capacity unaltered. Consequently, the maximum work per unit volume—the work density—is considered constant. Invertebrate muscle also varies in muscle ultrastructure, i.e. actin and myosin filament lengths. Increasing actin and myosin filament lengths increases force capacity, but the effect on muscle fibre displacement, and thus work, capacity is unclear. We use a sliding-filament muscle model to predict the effect of actin and myosin filament lengths on these mechanical parameters for both idealized sarcomeres with fixed actin : myosin length ratios, and for real sarcomeres with known filament lengths. Increasing actin and myosin filament lengths increases stress without reducing strain capacity. A muscle with longer actin and myosin filaments can generate larger force over the same displacement and has a higher work density, so seemingly bypassing an established trade-off. However, real sarcomeres deviate from the idealized length ratio suggesting unidentified constraints or selective pressures.
Date Issued
2024-05-22
Date Acceptance
2024-03-28
Citation
Journal of the Royal Society Interface, 2024, 21 (214)
ISSN
1742-5689
Publisher
The Royal Society
Journal / Book Title
Journal of the Royal Society Interface
Volume
21
Issue
214
Copyright Statement
© 2024 The Authors. 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.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/38774960
Subjects
actin
CLAW CLOSER
CLOSER MUSCLES
CONTRACTILE PROPERTIES
FILAMENT LATTICE
FLIGHT-MUSCLE
invertebrate
INVERTEBRATE MUSCLES
LAMSA
Multidisciplinary Sciences
muscle work density
musculoskeletal dynamics
MYOFIBRILLAR PROTEIN
myosin
SARCOMERE-LENGTH
Science & Technology
Science & Technology - Other Topics
STRIATED-MUSCLE
X-RAY
Publication Status
Published
Coverage Spatial
England
Article Number
20230658
Date Publish Online
2024-05-22