Evetovich T K, Housh T J, Weir J P, Johnson G O, Smith D B, Ebersole K T
Department of Health and Human Performance, University of Nebraska-Lincoln, USA.
Electromyogr Clin Neurophysiol. 1999 Mar;39(2):123-7.
The purpose of the present investigation was to examine the effects of knee angular velocity on the mean power frequency (MPF) and amplitude of the mechanomyographic (MMG) signal during maximal eccentric (ECC) isokinetic muscle actions. Eleven adult subjects performed maximal ECC muscle actions of the leg extensors on a calibrated Cybex 6000 dynamometer at knee angular velocities of 60, 120, and 180 degrees.s-1. MMG was detected by a piezoelectric crystal contact sensor placed over the vastus lateralis muscle. There were no significant (p > 0.05) velocity-related changes in ECC peak torque (PT) or MMG MPF, however, the mean MMG amplitude value at 60 degrees.s-1 was significantly less (p < 0.05) than that at 180 degrees.s-1. These results did not support our previous hypothesis that the velocity-related increase in MMG amplitude for maximal ECC isokinetic muscle actions was due to selective recruitment of fast twitch fibers and derecruitment of slow twitch fibers with increasing velocity.
本研究的目的是考察在最大离心（ECC）等速肌肉动作过程中，膝关节角速度对肌机械图（MMG）信号的平均功率频率（MPF）和幅度的影响。11名成年受试者在校准后的Cybex 6000测力计上，以60、120和180度·秒⁻¹的膝关节角速度进行腿部伸肌的最大离心肌肉动作。通过置于股外侧肌上的压电晶体接触式传感器检测MMG。ECC峰值扭矩（PT）或MMG的MPF与速度相关的变化无显著差异（p>0.05），然而，60度·秒⁻¹时的平均MMG幅度值显著低于（p<0.05）180度·秒⁻¹时的值。这些结果并不支持我们之前的假设，即最大离心等速肌肉动作中MMG幅度随速度增加而增大是由于快速抽搐纤维的选择性募集和慢速抽搐纤维随速度增加而解募集。
