Coburn Jared W, Housh Terry J, Malek Moh H, Weir Joseph P, Cramer Joel T, Beck Travis W, Johnson Glen O
Department of Kinesiology, California State University, Fullerton, 800 N. State College Blvd., KHS-235, Fullerton, California 92834-6870, USA.
Muscle Nerve. 2006 May;33(5):664-71. doi: 10.1002/mus.20509.
Little is known regarding the modulation of torque during eccentric muscle actions. Mechanomyographic (MMG) and electromyographic (EMG) signals have been used to examine motor control strategies. The purpose of this study was to examine the MMG and EMG amplitude and frequency in relation to torque during eccentric muscle contractions. Eight women performed eccentric leg extension muscle contractions at 10-100% of peak torque (PT). A piezoelectric crystal contact sensor and bipolar surface electrodes were placed on the vastus medialis to detect the MMG and EMG signals. Polynomial regression analyses indicated that EMG amplitude (r(2)=0.994) and MMG wavelet center frequency (CF) (r(2)=0.846) increased linearly to 100% eccentric PT, whereas there were no significant relationships for EMG wavelet CF or MMG amplitude and eccentric torque. These results suggested that eccentric torque is primarily modulated through changes in motor unit firing rate.
关于离心肌肉动作过程中扭矩的调节，人们了解甚少。机械肌电图（MMG）和肌电图（EMG）信号已被用于研究运动控制策略。本研究的目的是研究离心肌肉收缩过程中MMG和EMG的幅度及频率与扭矩的关系。八名女性以峰值扭矩（PT）的10%-100%进行离心腿部伸展肌肉收缩。将一个压电晶体接触传感器和双极表面电极置于股内侧肌上，以检测MMG和EMG信号。多项式回归分析表明，EMG幅度（r(2)=0.994）和MMG小波中心频率（CF）（r(2)=0.846）随离心PT线性增加至100%，而EMG小波CF或MMG幅度与离心扭矩之间无显著关系。这些结果表明，离心扭矩主要通过运动单位放电频率的变化进行调节。
