The character of muscle endurance during isometric contraction

我们的研究目的是利用肌电图（EMG）功率谱分析来研究几种肌肉的特征。45名健康受试者（22名男性和23名女性）进行了120秒的无支撑躯干握住测试。在每个竖脊肌L1水平放置记录表面电极。中位数频率（MF）、平均工频（MPF）和过零率（ZCR）使用ME3000P快速傅立叶变换频谱分析程序进行评估。男性背部肌肉疲劳各指标的负斜率明显大于女性。我们的研究结果还显示，健康成年女性的肌肉耐力高于男性。采用表面肌电功率谱分析方法，对10名偏瘫男性和10名健康男性进行了躯干保持试验。受影响的背部肌肉负MF斜率与未受影响的背部肌肉负MF斜率无显著差异。采用表面肌功率谱分析方法，比较了6名轮椅马拉松截瘫优等生与6名正常人的肱三头肌耐力的差异。对照组肱三头肌疲劳各指标的负斜率明显大于运动员。我们的研究结果还显示，优秀运动员的肌肉耐力高于对照组。

The purpose of our studies is to investigate the characters of several kinds of muscles using electromyographic (EMG) power spectral analyses.Forty-five healthy subjects (22 men and 23 women) were studied during an unsupported trunk holding test for 120 seconds. Recording surface electrodes were placed over each erector spinae muscle at L1 level. Median frequency (MF), mean power frequency (MPF) and zero crossing rate (ZCR) were evaluated using the ME3000P Fast Fourier Transform spectrum analysis program. The negative slopes of all indices of back muscle fatigue were significantly steeper in men than women. Our results also showed a higher muscle endurance in healthy adult women than in men.Ten hemiplegic men and ten healthy men were studied during a trunk holding test using surface EMG power spectrum analysis. The negative MF slope of the affected back muscle was not significantly different from that of the unaffected.The difference of triceps muscle endurance between six paraplegic superior athletes of wheel-chair marathon and six control paraplegic men were examined using surface EMG power spectrum analysis. The negative slopes of all indices of triceps muscle fatigue were significantly steeper in control than in athletes. Our results also showed a higher muscle endurance in superior athletes than in control men.