The Energy of Muscle Contraction. I. Tissue Force and Deformation During Fixed-End Contractions

Resource type
Date created
2020-08-31
Authors/Contributors
Abstract
During contraction the energy of muscle tissue increases due to energy from the hydrolysis of ATP. This energy is distributed across the tissue as strain-energy potentials in the contractile elements, strain-energy potential from the 3D deformation of the base-material tissue (containing cellular and extracellular matrix effects), energy related to changes in the muscle's nearly incompressible volume and external work done at the muscle surface. Thus, energy is redistributed through the muscle's tissue as it contracts, with only a component of this energy being used to do mechanical work and develop forces in the muscle's longitudinal direction. Understanding how the strain-energy potentials are redistributed through the muscle tissue will help enlighten why the mechanical performance of whole muscle in its longitudinal direction does not match the performance that would be expected from the contractile elements alone. Here we demonstrate these physical effects using a 3D muscle model based on the finite element method. The tissue deformations within contracting muscle are large, and so the mechanics of contraction were explained using the principles of continuum mechanics for large deformations. We present simulations of a contracting medial gastrocnemius muscle, showing tissue deformations that mirror observations from magnetic resonance imaging. This paper tracks the redistribution of strain-energy potentials through the muscle tissue during fixed-end contractions, and shows how fibre shortening, pennation angle, transverse bulging and anisotropy in the stress and strain of the muscle tissue are all related to the interaction between the material properties of the muscle and the action of the contractile elements.
Document
Identifier
DOI: 10.3389/fphys.2020.00813
Published as
Wakeling, J. M., Ross, S. A., Ryan, D. S., Bolsterlee, B., Konno, R., Domínguez, S., & Nigam, N. (2020). The Energy of Muscle Contraction. I. Tissue Force and Deformation During Fixed-End Contractions. Frontiers in Physiology, 11, 813. https://doi.org/10.3389/fphys.2020.00813.
Publication title
Frontiers in Physiology
Document title
The Energy of Muscle Contraction. I. Tissue Force and Deformation During Fixed-End Contractions
Date
2020
Volume
11
Publisher DOI
10.3389/fphys.2020.00813
Copyright statement
Copyright is held by the author(s).
Scholarly level
Peer reviewed?
Yes
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Attachment Size
fphys-11-00813.pdf 5.27 MB