目的　研究在静态负荷条件下肱二头肌和腰部脊竖肌疲劳发生、发展过程中的表面肌电 (SEMG)变化特征。方法　 14名受试者分别参加肱二头肌和腰部脊竖肌等长运动负荷实验 ,取表面肌电信号进行FFT功率谱及其功率谱二维地形图分析。结果　 2种负荷条件下 ,频域指标———平均功率频率 (MPF)和中位频率 (MF)的时间序列曲线均呈现直线递减变化 ;同时功率谱二维地形图分析呈现不同的变化规律。结论　不同类型的肌肉在疲劳过程中MPF和MF的下降所包含的信息不尽相同 ,并且主要表现为SEMG信号功率谱的带宽和分量值上的差异。 Objective To study the changes of the surface electromyography (SEMG) in the development and fatigue of the biceps and lumbar vertebrae under static load. Methods Fourteen subjects participated in the isometric exercise load test of biceps and lumbar vertebrae respectively. The surface EMG signals were taken for FFT power spectrum and power spectrum two-dimensional topographic analysis. Results Under the two kinds of loading conditions, the time series curves of frequency domain index (MPF) and median frequency (MF) all presented linear decreasing changes. At the same time, the two-dimensional topographic maps of power spectrum showed different changing rules. Conclusions The information contained in different types of muscle during the fatigue process is different from that of MPF and MF, and mainly shows the difference in the bandwidth and the component of the SEMG signal power spectrum.