Boccia Gennaro, Dardanello Davide, Tarperi Cantor, Rosso Valeria, Festa Luca, La Torre Antonio, Pellegrini Barbara, Schena Federico, Rainoldi Alberto
CeRiSM Research Center 'Sport, Mountain, and Health', via del Ben 5/b, Rovereto, (TN) 38068, Italy. Department of Medical Sciences, Motor Science Research Center, School of Exercise & Sport Sciences, SUISM, University of Turin, 12, piazza Bernini, Torino 10143, Italy.
Physiol Meas. 2017 Feb;38(2):233-240. doi: 10.1088/1361-6579/aa5139. Epub 2017 Jan 18.
Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity (CV) changes induced by an endurance run. The day before and immediately after a half-marathon run (21.097 km) 11 amateur runners performed maximum voluntary contractions (MVCs) of knee extensor muscles. During the MVC, multichannel EMG was recorded from the vastus lateralis and EMG amplitude and CV were calculated. After the run, knee extensors showed a decreased strength (-13 ± 9%, p = 0.001) together with a reduction in EMG amplitude (-13 ± 10%, p = 0.003) and in CV (-6 ± 8%, p = 0.032). Knee extensor strength loss positively correlated with vastus lateralis CV differences (r = 0.76, p = 0.006). Thus, the exercises-induced muscle fatigue was associated not only with a decrease in EMG amplitude, but also with a reduction in CV. This finding suggests that muscle fibers with higher CV (i.e. those with greater fiber size) were the most impaired during strength production after an endurance run.
监测表面肌电图（EMG）信号可为表征肌肉疲劳提供有用的见解，肌肉疲劳被定义为运动引起的力量损失。本实验研究了耐力跑引起的肌纤维传导速度（CV）变化。在半程马拉松跑（21.097公里）的前一天和结束后，11名业余跑步者对膝伸肌进行了最大自主收缩（MVC）。在MVC期间，从股外侧肌记录多通道EMG，并计算EMG幅度和CV。跑步后，膝伸肌的力量下降（-13±9%，p=0.001），同时EMG幅度降低（-13±10%，p=0.003），CV降低（-6±8%，p=0.032）。膝伸肌力量损失与股外侧肌CV差异呈正相关（r=0.
