par Marina, Michel;Torrado, Priscila;Duchateau, Jacques 
;Baudry, Stéphane
Référence International journal of sports medicine, 45, 2, page (125-133)
Publication Publié, 2023-05-01
;Baudry, Stéphane Référence International journal of sports medicine, 45, 2, page (125-133)
Publication Publié, 2023-05-01
Article révisé par les pairs
| Résumé : | The aim of the study was to assess neuromuscular changes during an intermittent fatiguing task designed to replicate fundamental actions and ergonomics of road race motorcycling. Twenty-eight participants repeated a sequence of submaximal brake-pulling and gas throttle actions, interspaced by one maximal brake-pulling, until failure. During the submaximal brake-pulling actions performed at 30 % MVC, force fluctuations, surface EMG, maximal M-wave (Mmax) and H-reflex were measured in the flexor digitorum superficialis. At the end of the task, the MVC force and associated EMG activity decreased (P<0.001) by 46% and 26%, respectively. During the task, force fluctuation and EMG activity increased gradually (106 % and 61 %, respectively) with respect to the pre-fatigue state (P≤ 0.029). The Mmax first phase did not change (P≥ 0.524), whereas the H-reflex amplitude, normalized to Mmax, increased (149%; P≤0.039). Noteworthy, the relative increase in H-reflex amplitude was correlated with the increase in EMG activity during the task (r= 0.63; P< 0.001). During the 10-min recovery, MVC force and EMG activity remained depressed (P≤ 0.05) whereas H-reflex amplitude and force fluctuation returned to pre-fatigue values. In conclusion, contrarily to other studies, our results bring forward that when mimicking motorcycling brake-pulling and gas throttle actions, supraspinal neural mechanisms primarily limit the duration of the performance. |
