Gueldich H, Zarrouk N, Chtourou H, Zghal F, Sahli S, Rebai H
Research Unit: "Education, Motricity, Sports and Health" (UR 15JS01), Higher Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia.
Laboratoire Adaptations Métabolique à l'Exercice en Conditions Physiologiques et Pathologiques (AME2P, EA 3533), Université Blaise Pascal, Clermont-Ferrand, France.
Int J Sports Med. 2017 Jan;38(1):41-47. doi: 10.1055/s-0042-115033. Epub 2016 Oct 28.
This study examined the effects of electrostimulation (ES) strength training at the same time-of-day on the diurnal fluctuations of maximal voluntary isometric contractions (MVIC) and surface electromyography (EMG). 20 male performed 3 MVICs of knee extension coupled with surface EMG before and after 5 weeks of 3 ES training sessions per week. Each ES training session consisted in 45 isometric contractions. The participants were randomly assigned to either a morning (MTG, 07:00-08:00 h) or an evening (ETG, 17:00-18:00 h) training group. Both groups performed the evaluation tests at 07:00 and 17:00 h. Before ES training, MVIC was significantly higher in the evening compared to the morning for all groups, but there was no significant difference between groups for all EMG parameters. After the ES training, the diurnal variations in MVIC were blunted in the MTG and persisted in the ETG. Significant time-of-day effect was noticed for all EMG parameters but there was no group effect. The elimination of the diurnal fluctuations of MVIC and the appearance of EMG variations by training in the morning hours suggest that neural adaptations are the main source of temporal specificity of neuromuscular performance after ES strength training.
本研究考察了在一天中的同一时间进行电刺激（ES）力量训练对最大自主等长收缩（MVIC）和表面肌电图（EMG）昼夜波动的影响。20名男性在每周进行3次ES训练课程，为期5周前后，进行了3次膝关节伸展的MVIC并同步记录表面EMG。每次ES训练课程包括45次等长收缩。参与者被随机分配到早晨（MTG，07:00 - 08:00）或晚上（ETG，17:00 - 18:00）训练组。两组均在07:00和17:00进行评估测试。在ES训练前，所有组的MVIC在晚上均显著高于早晨，但所有EMG参数在组间无显著差异。ES训练后，MTG组MVIC的昼夜变化变平缓，而ETG组则持续存在。所有EMG参数均出现显著的时间效应，但无组间效应。早晨训练消除了MVIC的昼夜波动并出现了EMG变化，这表明神经适应性是ES力量训练后神经肌肉性能时间特异性的主要来源。
