Biomechanics Laboratory, Department of Kinesiology, University of California, Los Angeles, Los Angeles, California, U.S.A.
J Electromyogr Kinesiol. 1992;2(2):69-80. doi: 10.1016/1050-6411(92)90018-E.
Limited conclusions concerning the variability in EMG patterns during cycling can be made from available data in the literature because of methodological differences which include electrode placement and experimental design. The purpose of this study was to monitor EMG signals from ten lower extremity muscles over a large number of pedalling cycles in experienced cyclists at constant workload and cadence. Variability across subjects was evaluated by calculating the coefficient of variation (CV) at 10% intervals of the pedalling cycle. Within subject EMG patterns were very consistent within a single trial. The single-joint hip and knee extensors (gluteus maximus, vastus medialis, and vastus lateralis) had the lowest CV values (less than 30%). This low variability appears to support their role as power generators. Variability was generally higher in the hamstring muscles with two biceps femoris patterns emerging despite relatively similar experimental conditions. EMG signals from surface and fine wire electrodes for the hamstring muscles were compared for possible contribution to the discrepancies in the EMG profiles. Fine wire EMG data were quite similar to those obtained using surface electrodes, indicating that crosstalk had minimal effect, in general, on the hamstring signals. The tibialis anterior, gastrocnemius, and soleus muscles displayed fairly repeatable patterns, with variability highest in the first 20% of the pedalling cycle for all muscles studied.
由于在电极放置和实验设计方面存在方法学差异，从现有文献中的数据可以得出有关骑行过程中肌电图模式变异性的有限结论。本研究的目的是在恒定工作量和踏频下，监测经验丰富的自行车运动员在大量踩踏周期中来自十个下肢肌肉的肌电图信号。通过计算踩踏周期的 10%间隔的变异系数（CV）来评估受试者之间的变异性。在单次试验中，单关节髋关节和膝关节伸肌（臀大肌、股直肌和股外侧肌）的 CV 值最低（小于 30%）。这种低变异性似乎支持它们作为动力发生器的作用。尽管实验条件相对相似，但腘绳肌的变异性通常更高，出现了两种股二头肌模式。尽管实验条件相对相似，但仍出现了两种股二头肌模式。尽管实验条件相对相似，但仍出现了两种股二头肌模式。对表面和细钢丝电极的肌电图信号进行了比较，以确定它们是否对肌电图曲线的差异有贡献。细钢丝肌电图数据与使用表面电极获得的数据非常相似，表明串扰通常对腘绳肌信号的影响很小。胫骨前肌、腓肠肌和比目鱼肌显示出相当可重复的模式，所有研究肌肉的变异性在踩踏周期的前 20%最高。
