基于幅频联合分析法对肌肉疲劳状态下表面肌电信号时、频域变化规律的研究

The Study of the Surface Electromyography Variation in Time and Frequency Domain When Fatigue in Muscle Takes Place Based on Joint Analysis of Spectrum and Amplitude

目的:通过对肌肉疲劳状态下表面肌电信号(sEMG)的提取,利用幅频联合分析的方法探讨sEMG作为肌肉生理特征信号在疲劳发生过程中的变化规律。方法:5名健康男性左右手臂分别进行一次实验,实验过程中,手臂自然下垂,前臂抬起至水平,与上臂成90°角,前臂上悬挂重量为5 Kg的重物,使肌肉等长收缩8 min,采用英国BIOPAC公司生产的MP150及其肌电采集模块同步记录肌肉的表面肌电信号,使用The MathWorks公司的MATLAB7.0软件,在信号3min、5 min、7 min后各取20 s进行幅频联合分析。结果:sEMG随着肌肉疲劳状态的加剧,信号幅值平均值明显增大,功率谱密度发生变化,平均功率频率(MPF)、中位频率(MF)明显减小。结论:表面肌电信号的幅频联合分析法为进一步深入研究肌肉疲劳状态下表面肌电信号的变化提供了方法支撑和理论依据。

Objective： We extract the surface EMG （sEMG） when fatigue in muscle take place, and study the changes of sEMG as a physiological characteristic signal when fatigue occur in muscle by the method of joint analysis of spectrum and amplitude （JASA）. Methods： 5 healthy men＇s left and right arms carry on the experiment separately, during the experiment, the arm should be naturally sagging such that： the forearm forms the right angle with the upper arm. A 5kg item is hung on the wrist, which eanses isometric contraction of the biceps for 8minutes. The myo-electricity is gathered by MP150 module （BIOPAC corporation, UK）, MATLAB software （ver7.0, MathWorks corporation, US） is used to analyze the signals by JASA. Results： As the muscle fatigue occurs, the mean of sEMG amplitude increases significantly, meanwhile, the power spectral density changes： both mean power frequency and median frequency reduce significantly. Conclusion： The JASA method provides methodological support and theoretical basis to further researches of the change of sEMG when muscle fatigue occurs.