等动屈伸运动诱发下肢膝关节肌肉疲劳过程中表面肌电信号的特征分析

摘要

目的：了解健康成年人下肢膝关节等动屈伸运动至疲劳过程中下肢股内侧肌表面肌电信号（sEMG）的特征，为 sEMG在动力性运动中的广泛应用提供依据。方法：选择在校男性大学生10人，使用艾力尔（Ariel）等动训练仪在60°s－1运动速度下诱发下肢股内外侧肌疲劳，同时使用 ME6000表面肌电仪记录2块肌肉的 sEMG，对其时域指标均方根振幅（RMS）和积分肌电（iEMG）以及频域指标中位频率（MF）和平均功率频率（MPF）进行分析。结果：在膝关节等速屈伸运动至疲劳过程中股内侧肌的时域指标 RMS和 iEMG显著上升（P＜0.05），疲劳对 iEMG影响的效应尺度大于 RMS；频域指标 MF和 MPF显著下降（P＜0.05），疲劳对 MPF影响的效应尺度大于 MF；肌肉疲劳过程中 iEMG 增加率显著高于 RMS （P＜0.05）， MPF 下降率显著大于 MF （P＜0.05）。结论：时域指标 iEMG以及频域指标 MPF可以作为评价动力性肌肉疲劳的敏感指标。%Objective To understand the characteristics of surface electromyography (sEMG)of vastus medialis muscle fatigue induced by isokinetic flexion and extension movement, and to further provide references for the application of sEMG on dynamical movements.Methods Arial isokinetic equipment and ME6000 equipment were combined to analyze the time domain indices including root mean square (RMS ) integrated electromyography (iEMG)and spectrum indices including median frequency (MF)and mean power frequency (MPF)for vastus medialis from ten students from Shenyang Sport University during isokinetic fatigue.Results During the isokinetic muscle fatigue the RMS and iEMG were significantly increased (P<0.05),accompanying with higher effect sizes for iEMG than for RMS. As for the spectrum indices,MF and MPF were significantly decreased (P<0.05)with larger effect sizes for MPF than for MF. The increase rate of iEMG was significantly higher in iEMG than RMS (P<0.05),and the decline rate of MPF was larger than MF (P<0.05).Conclusion The iEMG as a time domain index and MPF as a spectrum index can be sensitive indexes to assess the dynamic muscle fatigue.