Garcia-Sillero Manuel, Chulvi-Medrano Iván, Maroto-Izquierdo Sergio, Bonilla Diego A, Vargas-Molina Salvador, Benítez-Porres Javier
Faculty of Sport Sciences, EADE-University of Wales Trinity Saint David, 29018 Málaga, Spain.
Sport Performance and Physical Fitness Research Group (UIRFIDE), Department of Physical and Sports Education, University of Valencia, 46010 Valencia, Spain.
J Clin Med. 2022 Sep 3;11(17):5220. doi: 10.3390/jcm11175220.
This study aimed to evaluate the effects of preceding anodal transcranial direct stimulation (a-tDCS) over the dorsolateral prefrontal cortex (DLPFC) during the back squat exercise on movement velocity and surface electromyographic (sEMG) activity. Thirteen healthy, well-trained, male firefighters (34.72 ± 3.33 years; 178 ± 7.61 cm; 76.85 ± 11.21 kg; 26.8 ± 4.2 kg·m−2; back squat 1-repetition maximum 141.5 ± 16.3 kg) completed this randomised double-blinded sham-controlled crossover study. After familiarisation and basal measurements, participants attended the laboratory on two occasions separated by 72 h to receive either Sham or a-tDCS (current intensity of 2 mA for 20 min). Immediately after stimulation, participants completed three sets of 12 repetitions (70% of 1-RM) with three minutes of recovery between sets monitored with a linear position transducer. The sEMG of the rectus femoris (RF) and vastus lateralis (VL) of both legs were recorded. No significant differences were observed between a-tDCS and Sham interventions on mean concentric velocity at any set (p > 0.05). Velocity loss and effort index were significantly higher (p < 0.05) in set 3 compared to set 1 only in the a-tDCS group. The right-leg RM and right-leg VL elicited the greatest muscle activation during set 1 after a-tDCS and Sham, respectively (p < 0.05). Our results revealed that a-tDCS over the DLPFC might impact movement velocity or fatigue tolerance in well-trained individuals. Notwithstanding, significant differences in dominant-leg muscle activity were found both in a-tDCS and Sham.
本研究旨在评估在深蹲运动期间，对背外侧前额叶皮质（DLPFC）进行阳极经颅直流电刺激（a-tDCS）对运动速度和表面肌电图（sEMG）活动的影响。13名健康、训练有素的男性消防员（年龄34.72±3.33岁；身高178±7.61厘米；体重76.85±11.21千克；身体质量指数26.8±4.2千克·米−2；深蹲一次最大重量141.5±16.3千克）完成了这项随机双盲假刺激对照交叉研究。在熟悉流程和进行基础测量后，参与者在间隔72小时的两个时间段到实验室，分别接受假刺激或a-tDCS（电流强度2毫安，持续20分钟）。刺激结束后，参与者立即进行三组，每组12次重复动作（1-RM的70%），组间休息三分钟，使用线性位置传感器监测。记录双腿股直肌（RF）和股外侧肌（VL）的sEMG。在任何一组中，a-tDCS和假刺激干预在平均向心速度上均未观察到显著差异（p>0.05）。仅在a-tDCS组中，与第一组相比，第三组的速度损失和用力指数显著更高（p<0.05）。在a-tDCS和假刺激后，第一组中右腿RM和右腿VL分别引起最大肌肉激活（p<0.05）。我们的结果显示，对DLPFC进行a-tDCS可能会影响训练有素个体的运动速度或疲劳耐受性。尽管如此，在a-tDCS和假刺激中均发现优势腿肌肉活动存在显著差异。
