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Localized and systemic variations in central motor drive at different local skin and muscle temperatures

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posted on 14.06.2017 by Alex Lloyd, Lewis Picton, Margherita Raccuglia, Simon Hodder, George Havenith
This study investigated the ability to sustain quadriceps central motor drive while subjected to localized heat and metaboreceptive feedback from the contralateral leg. Eight active males each completed two counter-balanced trials, in which muscle temperature (Tm) of a single-leg (TEMP-LEG) was altered to 29.4 (COOL) or 37.6°C (WARM), while the contralateral leg (CL-LEG) remained thermoneutral; 35.3 and 35.2°C Tm in COOL and WARM respectively. To activate metaboreceptive feedback, participants first performed one 120-s isometric maximal voluntary contraction (MVC) of the knee extensors in the TEMP-LEG, immediately followed by post-exercise muscle ischemia (PEMI) via femoral blood flow occlusion. To assess central motor drive of a remote muscle group immediately following PEMI, another 120-s MVC was subsequently performed in the CL-LEG. Voluntary muscle activation (VA) was assessed using the twitch interpolation method. Perceived mental effort and limb discomfort were also recorded. In a cooled muscle, a significant increase in mean force output and mean VA (force, p<0.001; VA, p<0.05) as well as a significant decrease in limb discomfort (p<0.05) occurred during the sustained MVC in the TEMP-LEG. However, no differences between Tm were observed in mean force output, mean VA or limb discomfort during the sustained MVC in the CL-LEG (Force, p=0.33; VA, p>0.68, limb discomfort, p=0.73). The present findings suggest that elevated local Tsk and Tm can increase limb discomfort and decrease central motor drive, but this does not limit systemic motor activation of a thermoneutral muscle group.

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Published in

American Journal of Physiology: Regulatory, Integrative and Comparative Physiology

Volume

313

Issue

3

Pages

R219-228

Citation

LLOYD, A. ... et al., 2017. Localized and systemic variations in central motor drive at different local skin and muscle temperatures. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology. 313(3), pp.R219-228.

Publisher

© American Journal of Physiology-Regulatory, Integrative and Comparative Physiology

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

05/06/2017

Publication date

2017-09-01

Copyright date

2017

Notes

This article was published in the AJP - Regulatory, Integrative and Comparative Physiology [© APS] and the definitive version is available at: https://doi.org/10.1152/ajpregu.00055.2017

ISSN

0363-6119

Language

en

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