Additional in-series compliance reduces muscle force summation and alters the time course of force relaxation during fixed-end contractions

Mayfield, Dean L., Launikonis, Bradley S., Cresswell, Andrew G. and Lichtwark, Glen A. (2016) Additional in-series compliance reduces muscle force summation and alters the time course of force relaxation during fixed-end contractions. Journal of Experimental Biology, 219 22: 3587-3596. doi:10.1242/jeb.143123


Author Mayfield, Dean L.
Launikonis, Bradley S.
Cresswell, Andrew G.
Lichtwark, Glen A.
Title Additional in-series compliance reduces muscle force summation and alters the time course of force relaxation during fixed-end contractions
Journal name Journal of Experimental Biology   Check publisher's open access policy
ISSN 0022-0949
1477-9145
Publication date 2016-01-01
Year available 2016
Sub-type Article (original research)
DOI 10.1242/jeb.143123
Open Access Status DOI
Volume 219
Issue 22
Start page 3587
End page 3596
Total pages 28
Place of publication Cambridge, United Kingdom
Publisher The Company of Biologists
Language eng
Abstract There are high mechanical demands placed on skeletal muscles in movements requiring rapid acceleration of the body or its limbs. Tendons are responsible for transmitting muscle forces, but, due to their elasticity, can manipulate the mechanics of the internal contractile apparatus. Shortening of the contractile apparatus against the stretch of tendon affects force generation according to known mechanical properties, however, the extent to which differences in tendon compliance alter force development in response to a burst of electrical impulses is unclear. To establish the influence of series compliance on force summation, we studied electrically evoked doublet contractions in the cane toad peroneus muscle in the presence and absence of a compliant artificial tendon. Additional series compliance reduced tetanic force by two-thirds, a finding predicted based on the force-length property of skeletal muscle. Doublet force and force-time integral expressed relative to the twitch were also reduced by additional series compliance. Active shortening over a larger range of the ascending limb of the force-length curve and at a higher velocity, leading to a progressive reduction in force-generating potential, could be responsible. Muscle-tendon interaction may also explain the accelerated time course of force relaxation in the presence of additional compliance. Our findings suggest that a compliant tendon limits force summation under constant-length conditions. However, high series compliance can be mechanically advantageous when a muscle-tendon unit is actively stretched, permitting muscle fibres to generate force almost isometrically, as shown during stretch-shorten cycles in locomotor activities. Restricting active shortening would likely favour rapid force development.
Keyword Series elastic compliance
Tendon stiffness
Muscle force
Muscle mechanics
Relaxation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Biomedical Sciences Publications
School of Human Movement and Nutrition Sciences Publications
 
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Created: Thu, 06 Oct 2016, 01:32:41 EST by Sandrine Ducrot on behalf of School of Human Movement and Nutrition Sciences