中文摘要：

目的：探讨低频电刺激过程中大鼠骨骼肌肌张力和肌电信号的变化特征。方法：对12只雄性SD大鼠腓肠肌进行低频电刺激，采用SMUP—E型生物信号处理系统同步记录其肌张力及肌电信号的变化，并分别取刺激0、5、10、20、40min时的肌电信号和肌张力值进行比较分析。结果：（1）随刺激时间延长，腓肠肌肌张力峰一峰（P—P）值及肌张力微分值逐渐降低，与刺激开始时相比，刺激10min时即有显著性差异（P〈0．01）；而疲劳指数（FI）则随刺激时间延长逐渐增加，刺激40min时高达52．14％。（2）肌电振幅P—P值及肌电图（EMG）时频指标——肌电积分（IEMG）、平均功率频率（MPF）和中位频率（MF）值均随刺激时间延长而逐渐降低。与刺激开始时相比，刺激5min时MPF已显著降低（P〈0．05），而肌电振幅P—P值及IEMG值在刺激10min时才开始显著降低（P〈0．05）；尽管MF值随刺激时间延长有所降低，但各时间点差异无统计学意义（P〉0．05）。结论：低频电刺激可诱发大鼠腓肠肌疲劳，MPF在反映疲劳的敏感性方面优于IEMG。

英文摘要：

Objective To investigate the characteristic changes in muscular tension and EMG signal in rats during electric stimulation with low-frequency. Methods The gastrocnemius of 12 male SD rats was treated by low-frequency electric stimulation. The changes in muscular tension and EMG signals were recorded with SMUP- E biological signal processing system, then the parameters of EMG and muscular tension at 0, 5, 10, 20 and 40rain were compared respectively. Results （1） As the stimulation time prolonged, the peak-to-peak values and differential values of muscular tension were decreased gradually, and both of them revealed very significant differences at 10rain as compared with the beginning of the stimulation （P〈0.01）. The fatigue index （FI） increased with the prolonging of stimulation time, and reached to 52. 14% at 40rnin. （2） As the stimulation time prolonged,the peak-to-peak values of EMG amplitude, IEMG, MPF and MF decreased gradually. The significant differences in MPF, and IEMG and peak-to-peak values of EMG amplitude appeared at 5rain and 10rain respectively as compared with the beginning of the stimulation （P〈0. 05）. The MF decreased gradually with prolonging of the stimulation time while no significant difference was seen （P〈0.05）. Conclusion The gastroenemius fatigue could be induced by low-frequency electric stimulation. The changes in EMG signals could reflect the occurrence and degree of muscle fatigue. The sensibility of MPF was higher than that of IEMG and MF in detecting the gastrocnemius fatigue.