Beck T W
Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019-6081, USA.
Electromyogr Clin Neurophysiol. 2009 Jan-Feb;49(1):35-42.
The purpose of this study was to examine the patterns of responses for mechanomyographic (MMG) amplitude versus isometric torque in different frequency bands for the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) muscles. Eleven men (mean +/- SD age = 20.1 +/- 1.1 yrs) performed submaximal to maximal isometric step muscle actions of the dominant leg extensors from 10% to 100% of the maximum voluntary contraction (MVC). During each muscle action, three separate surface mechanomyographic (MMG) signals were detected from the VL, RF and VM. Each MMG signal was decomposed into 9 different frequency bands (5-15, 15-25, 25-35, 35-45, 45-55, 55-65, 65-75, 75-85, and 85-95 Hz), and the root-mean-square amplitude of the signal in each frequency band was calculated. The results showed that for the VL and RF muscles, MMG amplitude plateaued from 80-100% MVC in the 15-25 and 25-35 Hz frequency bands. For the VM, however, the plateau in MMG amplitude from 80-100% MVC occurred in the 5-15 and 15-25 Hz bands. These findings indicated that there were both muscle- and frequency-specific discrepancies in the MMG amplitude versus isometric torque relationship that could be due to differences in muscle architecture and/or fiber type composition.
本研究的目的是检测股外侧肌（VL）、股直肌（RF）和股内侧肌（VM）在不同频段的肌机械图（MMG）振幅与等长扭矩的反应模式。11名男性（平均±标准差年龄 = 20.1±1.1岁）对优势腿伸肌进行了从最大自主收缩（MVC）的10%到100%的次最大到最大等长跨步肌肉动作。在每次肌肉动作期间，从VL、RF和VM检测到三个独立的表面肌机械图（MMG）信号。每个MMG信号被分解为9个不同的频段（5 - 15、15 - 25、25 - 35、35 - 45、45 - 55、55 - 65、65 - 75、75 - 85和85 - 95赫兹），并计算每个频段信号的均方根振幅。结果表明，对于VL和RF肌肉，在15 - 25和25 - 35赫兹频段，MMG振幅在80 - 100%MVC时趋于平稳。然而，对于VM，MMG振幅在80 - 100%MVC时的平稳出现在5 - 15和15 - 25赫兹频段。这些发现表明，在MMG振幅与等长扭矩关系中存在肌肉和频率特异性差异，这可能是由于肌肉结构和/或纤维类型组成的差异所致。
