Leonardo Henrique Perinotto Abdalla, Ryan Michael Broxterman, Thomas Jackson Barstow, Camila Coelho Greco, Benedito Sérgio Denadai

16
Jul 20, 2021
Experimental Physiology
DOI :
10.1113/ep089638
Article show_chart
New Finding What is the central question of this study? Does muscle size, maximal force and exercise intensity influence the recovery time constant for the finite impulse above critical torque (τIET′)? What is the main finding and its importance? This study showed that muscle size and maximal strength have different influences on the parameters of the hyperbolic torque ‐ Tlim relationship. Greater muscle size and maximal strength, as well as exercise at an intensity of 60% MVC, prolong τIET′ during intermittent isometric exercise. Muscle perfusion and O2 delivery limitations through muscle force generation appear to play a major role in defining the hyperbolic torque ‐ Tlim relationship. Therefore, we aimed to determine the influence of muscle size and maximal strength on the recovery time constant for the finite impulse above critical torque (τIET′). Ten men participated in the study and performed intermittent isometric tests until task‐failure (Tlim) for the knee‐extensors (KE 35% and 60% MVC) and plantar flexors (PF 60% MVC). The τIET′ was determined for each of these Tlim tests using the IET"BAL model. The IETʹ (9738 ± 3080 vs 2959 ± 1289 N · m · s) and ET (84.5 ± 7.1 vs 74.3 ± 12.7 N · m) were significantly lower for PF compared to KE (P < 0.05). Exercise tolerance (Tlim) was significantly longer for PF (239 ± 81 s) than KE (150 ± 55 s) at 60% MVC, and significantly longer for KE at 35% MVC (641 ± 158 s) than 60% MVC. The τIET′ was significantly faster at 35% MVC (641± 177 s) than 60% MVC (1840 ± 354 s) for KE, both of which were significantly slower than PF 60% MVC (317 ± 102 s). This study showed that τIET′ during intermittent isometric exercise is slower with greater muscle size and maximal strength. This article is protected by copyright. ...
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