Sandercock T G, Faulkner J A, Albers J W, Abbrecht P H
J Appl Physiol (1985). 1985 Apr;58(4):1073-9. doi: 10.1152/jappl.1985.58.4.1073.
Muscle fatigue is defined as a loss of tension development during constant stimulation. Although the relationship is not well documented, muscle fatigue has been inferred from electromyogram (EMG) signals. The purpose of this study was to determine the relationship between the amplitude and duration of single motor unit action potentials (MUAPs) and the loss of tension development (fatigue) in the medial gastrocnemius muscles of cats. Single motor units were fatigued by continuous stimulation at 10 or 80 Hz or with trains of 40-Hz stimuli. When motor units were stimulated at 10 Hz and with trains at 40 Hz (low frequency), tension declined and remained depressed during recovery. The changes in the MUAP correlated poorly with changes in tension. During and after stimulation at 80 Hz (high frequency), changes in the amplitude and duration of MUAPs correlated highly with changes in tension development. Since the EMG signal is dependent on a summation and cancellation of individual MUAPs, the EMG provides a reasonable estimate of high-frequency fatigue but an unreliable measure of low-frequency fatigue.
肌肉疲劳被定义为在持续刺激过程中张力发展的丧失。尽管这种关系尚无充分记录，但肌肉疲劳已可从肌电图（EMG）信号中推断出来。本研究的目的是确定猫的腓肠肌内侧单运动单位动作电位（MUAPs）的幅度和持续时间与张力发展丧失（疲劳）之间的关系。通过以10或80赫兹持续刺激或40赫兹刺激串使单个运动单位疲劳。当运动单位以10赫兹和40赫兹刺激串（低频）刺激时，张力下降并在恢复过程中持续降低。MUAP的变化与张力变化的相关性较差。在80赫兹（高频）刺激期间及之后，MUAPs的幅度和持续时间变化与张力发展变化高度相关。由于EMG信号依赖于单个MUAP的总和与抵消，EMG可对高频疲劳提供合理估计，但对低频疲劳的测量不可靠。
