Laboratory of Applied Physiology, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
Scand J Med Sci Sports. 2011 Dec;21(6):e412-20. doi: 10.1111/j.1600-0838.2011.01347.x. Epub 2011 Jun 15.
The purpose of this study was to compare the relationship between surface electromyography (EMG) and knee joint angle of the vastus intermedius muscle (VI) with the synergistic muscles in the quadriceps femoris (QF) muscle group. Fourteen healthy men performed maximal voluntary contractions during isometric knee extension at four knee joint angles from 90°, 115°, 140°, and 165° (180° being full extension). During the contractions, surface EMG was recorded at four muscle components of the QF muscle group: the VI, vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) muscles. The root mean square of the surface EMG at each knee joint angle was calculated and normalized by that at a knee joint angle of 90° for individual muscles. The normalized RMS of the VI muscle was significantly lower than those of the VL and RF muscles at the knee joint angles of 115° and 165° and those of the VL, VM, and RF muscles at the knee joint angle of 140° (P<0.05). The present results suggest that the neuromuscular activation of the VI muscle is regulated in a manner different from the alteration of the knee joint angle compared with other muscle components of the QF muscle group.
本研究旨在比较表面肌电图（EMG）与股四头肌（QF）肌群协同肌的股中间肌（VI）膝关节角度之间的关系。14 名健康男性在膝关节角度为 90°、115°、140°和 165°（180°为完全伸展）的等长膝关节伸展过程中进行最大自主收缩。在收缩过程中，记录了 QF 肌肉群的四个肌肉成分的表面 EMG：VI、股外侧肌（VL）、股内侧肌（VM）和股直肌（RF）。对每个膝关节角度的表面 EMG 的均方根进行计算，并将其归一化为膝关节角度为 90°时的个体肌肉的均方根。在膝关节角度为 115°和 165°时，VI 肌肉的归一化 RMS 明显低于 VL 和 RF 肌肉，在膝关节角度为 140°时，VI、VL、VM 和 RF 肌肉的归一化 RMS 也明显低于 VL、VM 和 RF 肌肉（P<0.05）。本研究结果表明，与 QF 肌群的其他肌肉成分相比，VI 肌肉的神经肌肉激活方式与膝关节角度的变化不同。
