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.
History
School
Design
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.
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/