当疲劳收缩与扭矩相匹配时,电机单元行为的差分调节与EMG相匹配
Justine R Magnuson1, Brian H Dalton, Chris J McNeil
1School of Health and Exercise Sciences and Centre for Heart, Lung and Vascular Health, The University of British Columbia, Kelowna, BC, CANADA.
Medicine and science in sports and exercise
|April 10, 2024
概括
在疲劳期间保持肌肉力量需要不同的神经战略. 匹配扭矩收缩增加了机动单元 (MU) 放电率,而匹配电肌图 (EMG) 收缩减少了它们以保持稳定性.
科学领域:
- 神经科学是一个神经科学.
- 运动生理学 运动生理学
- 发动机控制器的控制器
背景情况:
- 持续的亚最大同位数收缩使神经刺激能力的评估复杂化,原因是运动神经元池激活的增加.
- 匹配电肌图 (EMG) 收缩是诱导疲劳的一种新方法,但根本的神经生理学调整尚未得到充分理解.
研究的目的:
- 为了研究匹配扭矩和匹配EMG疲劳同度收缩之间的神经生理差异.
- 为了确定运动单元 (MU) 的放电率和肌肉力量/EMG稳定性是如何受到这两种疲劳协议的影响.
主要方法:
- 16名参与者在20%的最大自发收缩 (MVC) 扭矩或匹配的EMG水平下进行了10分钟的异比肘部曲.
- 表面EMG评估了全球中位数频率;细线电极记录了两腕的MU放电率.
- 在整个疲劳任务中评估了扭矩和EMG稳定性.
主要成果:
- 在匹配扭矩收缩过程中,发动机单元 (MU) 的放电率增加,扭矩稳定性下降.
- 在匹配的EMG收缩期间,MU放电率下降,而EMG稳定性没有变化.
- 在这两种条件下,观察到全球中位数频率的下降,在匹配扭矩后,与匹配EMG收缩相比,MVC扭矩损失更大.
结论:
- 匹配扭矩收缩需要增加MU放电率,牺牲扭矩稳定性以维持力.
- 匹配的EMG收缩允许降低MU放电率,保持EMG稳定性.
- 这些发现突出了用于在不同疲劳条件下维持肌肉活动的独特神经战略.
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