Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA.
Physiol Meas. 2010 Mar;31(3):339-61. doi: 10.1088/0967-3334/31/3/005. Epub 2010 Feb 3.
The purpose of the present study was to examine the stationarity of surface mechanomyographic (MMG) signals from the vastus lateralis, rectus femoris and vastus medialis during concentric isokinetic, eccentric isokinetic and isometric muscle actions of the leg extensors. Eleven healthy men (mean +/- SD age = 20.1 +/- 1.1 years) performed submaximal to maximal concentric isokinetic, eccentric isokinetic and isometric muscle actions of the leg extensors, and surface MMG signals were detected from the vastus lateralis, rectus femoris and vastus medialis. All surface MMG signals were tested for stationarity with a procedure that examined changes in the mean value, variance, mean frequency and standard deviation of the power spectrum over time. The results showed that the three muscle action types resulted in similar levels of signal nonstationarity. Thus, despite the fact that the isometric muscle actions were performed at a constant force level and with no change in muscle length, the level of signal nonstationarity was similar to that for the concentric and eccentric isokinetic muscle actions. Future studies need to be done to identify the mechanism(s) causing MMG signal nonstationarity during isometric muscle actions.
本研究旨在探讨股外侧肌、股直肌和股中间肌表面肌电（MMG）信号在等速向心、等速离心和等长肌肉收缩运动中的稳定性。11 名健康男性（平均年龄 +/- SD = 20.1 +/- 1.1 岁）进行了腿部伸展肌的亚最大至最大等速向心、等速离心和等长肌肉收缩运动，同时从股外侧肌、股直肌和股中间肌检测到表面 MMG 信号。使用一种检验均值、方差、均方根谱的均值和标准差随时间变化的程序来检验所有表面 MMG 信号的稳定性。结果表明，三种肌肉收缩运动类型导致相似程度的信号非稳定性。因此，尽管等长肌肉收缩运动是在恒定的力水平下进行的，且肌肉长度没有变化，但信号非稳定性的程度与等速向心和离心肌肉收缩运动相似。未来的研究需要确定导致等长肌肉收缩运动中 MMG 信号非稳定性的机制。
