Papaiordanidou Maria, Stevenot Jean-Damien, Mustacchi Valerie, Vanoncini Michele, Martin Alain
UMR7287, Institut des Sciences du Mouvement, CNRS, Faculté des Sciences du Sport, Aix-Marseille University, 163 avenue de Luminy, 13288, Marseille, France.
Muscle Nerve. 2014 Oct;50(4):604-7. doi: 10.1002/mus.24276. Epub 2014 Aug 30.
The aim of the study was to compare the fatigue induced by different electrical stimulation (ES) protocols. The triceps surae muscle of 8 healthy subjects was fatigued with 4 protocols (30 Hz-500 μs, 30 Hz-1 ms, 100 Hz-1 ms, and 100 Hz-500 μs), composed of 60 trains (4 s on-6 s off), delivered at an intensity evoking 30% of maximal voluntary contraction (MVC). Fatigue was quantified by ES and MVC torque decreases. The amplitude of the twitch delivered at the intensity and pulse width used in each fatiguing protocol (twitch at Istim ) was analyzed. All parameters decreased significantly after all protocols. The ES torque decrease correlated positively with the twitch decrease elicited at Istim only for the 30-Hz protocols. Results show that, during the 100-Hz protocols, phenomena not related to the fatigue of the solicited motor units may occur, including changes in the excitability threshold of the axonal terminal branches.
本研究的目的是比较不同电刺激（ES）方案所诱发的疲劳。对8名健康受试者的小腿三头肌采用4种方案（30Hz - 500μs、30Hz - 1ms、100Hz - 1ms和100Hz - 500μs）进行疲劳诱导，每种方案由60组刺激（4秒开启 - 6秒关闭）组成，刺激强度为最大自主收缩（MVC）的30%。通过ES和MVC扭矩降低来量化疲劳。分析了在每种疲劳方案所使用的强度和脉冲宽度下施加的单收缩幅度（I刺激时的单收缩）。所有方案后所有参数均显著下降。仅在30Hz方案中，ES扭矩降低与I刺激时引发的单收缩降低呈正相关。结果表明，在100Hz方案期间，可能会出现与所募集运动单位疲劳无关的现象，包括轴突终末分支兴奋性阈值的变化。
