The relationship between EMG median frequency and low frequency band amplitude changes at different levels of muscle capacity
The relationship between EMG median frequency and low frequency band amplitude changes at different levels of muscle capacity
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DOI：
10.1016/s0268-0033(02)00033-5
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发表时间：
2002-07-01
影响因子：
1.8
通讯作者：
Fujiwara, T
中科院分区：
文献类型：
--
作者：
Allison, GT;Fujiwara, T
Objective.目的：探讨表面肌电（EMG）高、低频幅值表征肌肉疲劳的有效性。采用受试者内（n=10）重复测量设计，在两种疲劳状态下等长收缩期间收集二头肌的表面肌电信号。背景。使用表面EMG功率谱的中值频率的偏移是评估肌肉疲劳的公知方法。疲劳还导致特定频带的幅度变化。频带分析的使用可能是在特定的实验环境中评估肌肉疲劳的一种替代选择。表面肌电轮廓的二头肌记录在1024赫兹在持续等长保持在60%的个人新鲜和疲劳的最大自愿等长扭矩。将功率谱的中值频率与低频（15-45 Hz）和高频（>95 Hz）频带的变化进行比较。中位频移与15-45 Hz带宽的幅值和高低频幅值比有密切关系。在不同的肌肉容量状态下，这种关联对于表现是相似的。频带振幅分析提供了类似的信息，中值频移等距条件下，并可能适合于特定的实验方案，在工作场所的疲劳研究。
Objective. To test the validity of high and low frequency band amplitudes of the surface electromyography (EMG) profile as representation of muscle fatigue.Design. A within subjects (n=10) repeated measures design was used to collect surface EMG signals from the biceps during an isometric contraction under two levels of fatigue status.Background. The use of the shift in the median frequency of the surface EMG power spectrum is a well known method of assessing muscle fatigue. Fatigue also results in amplitude changes of the specific frequency bands. The use of frequency band analysis may be an alternative option for the assessment of muscle fatigue in specific experimental settings.Methods. Surface EMG profiles of the biceps were recorded at 1024 Hz during a sustained isometric hold at 60% of the individuals fresh and fatigued maximal voluntary isometric torque. The median frequency of the power spectrum was compared with changes in the low frequency (15-45 Hz) and high frequency (>95 Hz) bands.Results. There was a close association between median frequency shift and the amplitude of the 15-45 Hz bandwidth and the high-low frequency amplitude ratio. The association was similar for performance under different muscle capacity states.Conclusions. Frequency band amplitude analysis provides similar information to median frequency shift under isometric conditions and may be suited to specific experimental protocols in workplace fatigue studies.