Hägg G M
Division of Applied Work Physiology, National Institute of Occupational Health, Solna, Sweden.
Med Biol Eng Comput. 1991 Sep;29(5):511-6. doi: 10.1007/BF02442323.
EMG was recorded during short test contractions performed during occupational work. Mean power frequency (MPF) and median frequency (MF), calculated from EMG spectra, and zero crossing rate (ZC) of the EMG signal were compared as estimators of local muscular fatigue. The results show that there is a systematic difference between the three estimates. The difference can be explained by dividing the effect of muscle fatigue on EMG spectra into a motor unit action potential velocity effect and a firing statistics effect. Furthermore, it is shown that the phenomenon of increasing estimators of EMG spectrum shift is unlikely to be caused by motor unit action potential velocity increase. Successive recruitment of new motor units is suggested as a feasible explanation.
在职业工作期间进行的短时间测试收缩过程中记录了肌电图。将从肌电图谱计算得出的平均功率频率（MPF）和中位数频率（MF）以及肌电信号的过零率（ZC）作为局部肌肉疲劳的估计指标进行了比较。结果表明，这三种估计之间存在系统性差异。这种差异可以通过将肌肉疲劳对肌电图谱的影响分为运动单位动作电位速度效应和放电统计效应来解释。此外，研究表明，肌电图谱偏移估计值增加的现象不太可能是由运动单位动作电位速度增加引起的。新运动单位的连续募集被认为是一种可行的解释。
