Oberg T, Sandsjö L, Kadefors R
Department of Biomechanics, University College of Health and Care, Jönköping, Sweden.
Eur J Appl Physiol Occup Physiol. 1990;61(5-6):362-9. doi: 10.1007/BF00236054.
In this study we have examined the variation of mean power frequency (MPF) in the electromyogram (EMG) from the non-fatigued trapezius muscle, with different external hand loads, in different shoulder joint positions, different torques and different planes of movement. The study was limited to the functional range of movement in the shoulder joint. It was performed on 19 healthy subjects. Surface EMG was recorded, analysed by means of a computer programme and examined by regression analysis. Normalized MPF values were calculated by dividing the MPF by the individual average MPF for all positions and loads. The results indicated no major variation in normalized MPF. The largest systematic variation of normalized MPF, +/- 8%, was related to joint angle. We have concluded that the MPF value obtained initially can be used within the functional range of movement to calculate the relative decrease in MPF as a result of muscle fatigue, and that the decrease is significant if it exceeds 8% of the initial value.
在本研究中，我们检测了非疲劳斜方肌肌电图（EMG）中平均功率频率（MPF）的变化情况，这些变化涉及不同的手部外部负荷、不同的肩关节位置、不同的扭矩以及不同的运动平面。该研究局限于肩关节的功能运动范围。研究对象为19名健康受试者。记录表面肌电图，通过计算机程序进行分析，并采用回归分析进行检验。通过将MPF除以所有位置和负荷下的个体平均MPF来计算标准化MPF值。结果表明标准化MPF无重大变化。标准化MPF的最大系统性变化为±8%，与关节角度有关。我们得出结论，最初获得的MPF值可在功能运动范围内用于计算由于肌肉疲劳导致的MPF相对下降，如果下降超过初始值的8%，则该下降具有显著性意义。
