Gerdle B, Henriksson-Larsén K, Lorentzon R, Wretling M L
Department of Physical Medicine and Rehabilitation, University of Umeå, Sweden.
Acta Physiol Scand. 1991 Aug;142(4):457-65. doi: 10.1111/j.1748-1716.1991.tb09180.x.
The aim of this study was to investigate whether the mean power frequency of the electromyogram of the knee extensors was force and/or muscle fibre-type dependent. Ten female subjects performed a gradually increasing static knee extension (5 seconds duration) using an isokinetic dynamometer. Electromyogram-signals were obtained from the vastus lateralis, vastus medialis and the rectus femoris muscles. The torque signal and the three electromyogram signals were recorded on a tape recorder. From the electromyogram recordings the mean power frequency and the signal amplitude were determined. Muscle biopsies were later obtained from the right vastus lateralis and stained for alkaline and acid mATPase for the determination of fibre-type proportion and areas. Both the mean power frequencies and the signal amplitudes of the three knee extensors were positively torque dependent. Furthermore it was found that the fibre type proportion and the regression coefficient of the torque (%)-mean power frequency relationship were positively correlated. Also a negative correlation existed between the type-1 (%) proportion and the intercept of the individual torque (%)-mean power frequency relationships. In contrast to proposed models of the electromyogram signal no correlation was found between the mean power frequency and the fibre area.
本研究的目的是调查膝伸肌肌电图的平均功率频率是否取决于力量和/或肌纤维类型。十名女性受试者使用等速测力计进行逐渐增加负荷的静态膝关节伸展（持续5秒）。从股外侧肌、股内侧肌和股直肌获取肌电信号。扭矩信号和三个肌电信号被记录在磁带录音机上。从肌电记录中确定平均功率频率和信号幅度。随后从右侧股外侧肌获取肌肉活检样本，用碱性和酸性mATP酶染色，以确定纤维类型比例和面积。三个膝伸肌的平均功率频率和信号幅度均与扭矩呈正相关。此外，发现纤维类型比例与扭矩（%）-平均功率频率关系的回归系数呈正相关。1型（%）比例与个体扭矩（%）-平均功率频率关系的截距之间也存在负相关。与肌电信号的现有模型相反，未发现平均功率频率与纤维面积之间存在相关性。
