疲劳相关表面肌电信号特征的非疲劳特异性研究

目的探讨静态运动负荷诱发肌肉疲劳过程中表面肌电信号 (sEMG)疲劳相关特征变化的非疲劳特异性。方法记录 1 0名被试者等长屈肘收缩 1min肱二头肌和肱三头肌sEMG的信号 ,分析MPF、MF、ZCR、AEMG和Lempel ziv复杂度各项疲劳相关性指标的变化 ,并测量肱三头肌在疲劳运动负荷试验前、后的MVC值。结果肱二头肌在持重负荷过程中MPF、MF、ZCR和Lempel ziv复杂度均随着负荷持续时间呈线性规律递减 ,AEMG呈线性规律递增 ;肱三头肌的MVC在疲劳运动负荷前后无明显变化 ,分别为( 1 4 .0± 3.2 )kg和 ( 1 4 .6± 2 .6)kg。但MPF、MF、ZCR和Lempel ziv复杂度也呈线性递减变化且变化率明显大于肱二头肌 ,而AEMG无明显变化。结论sEMG信号线性时、频和非线性复杂度的变化不具有肌肉疲劳特异性 ,疲劳可能不是造成上述指标变化的唯一因素。

Studies on the Non-fatigue Specificity of the Fatigue-related sEMG Signal Parameters

Objective: To investigate the non-fatigue specificity of the changes of the fatigue-related parameters of sEMG signal during muscle static contractions. Method: The sEMG signals of biceps brachii (BB) and triceps brachii (TB) were recorded in 10 subjects during 1 min sustained right elbow isometric flexion. Changes of a series of fatigue-related indices such as MPF, MF, ZCR, AEMG and Lempel-ziv complexity were then analyzed. MVCs of the extensor (TB) were measured before and immediately after fatiguing flexion. Result: MPF, MF, ZCR and Lempel-ziv complexity of BB all decreased regularly and linearly with continuation of contraction. Whereas AEMG of BB increased linearly. The MVCs of TB were (14.0 +/- 3.2)kg and (14.6 +/- 2.6)kg respectively before and after BB fatiguing contraction. But the slopes of decrease of MPF, MF, ZCR and Lempel-ziv complexity of TB were significantly steeper than those of BB. The AEMG of TB was almost unchanged. Conclusion: The changes of time- and frequency-domain indices and Lempel-ziv complexity of sEMG signal were not as a result of muscle fatigue specifically. Fatigue might not be the only factor that caused the changes of the indices mentioned above.