Kupa E J, Roy S H, Kandarian S C, De Luca C J
NeuroMuscular Research Center, Boston University, Massachusetts, USA.
J Appl Physiol (1985). 1995 Jul;79(1):23-32. doi: 10.1152/jappl.1995.79.1.23.
This paper describes an in vitro method for comparing surface-detected electromyographic median frequency (MF) and conduction velocity (CV) parameters with histochemical measurements of muscle fiber type composition and cross-sectional area (CSA). Electromyographic signals were recorded during electrically elicited tetanic contractions from rat soleus, extensor digitorum longus, and diaphragm muscles placed in an oxygenated Krebs bath. Fibers were typed as slow oxidative, fast oxidative glycolytic, and fast glycolytic based on histochemical enzyme stains. Muscles with a greater percentage of fast glycolytic and fast oxidative glycolytic fibers exhibited greater initial values of MF and CV as well as a greater reduction in these variables over the course of the contraction. Regression indicated that fiber type composition could be predicted based on two MF parameters. A weighted measure of muscle fiber CSA was found to be linearly related to both initial MF and CV. The results of this study suggest that MF and CV parameters recorded during a muscular contraction are related to muscle fiber type composition and muscle fiber CSA.
本文描述了一种体外方法，用于将表面检测到的肌电图中位频率（MF）和传导速度（CV）参数与肌肉纤维类型组成和横截面积（CSA）的组织化学测量结果进行比较。在置于充氧Krebs浴中的大鼠比目鱼肌、趾长伸肌和膈肌进行电诱发强直收缩期间记录肌电信号。根据组织化学酶染色将纤维分为慢氧化型、快氧化糖酵解型和快糖酵解型。快糖酵解纤维和快氧化糖酵解纤维比例较高的肌肉，其MF和CV的初始值较高，并且在收缩过程中这些变量的降低幅度也较大。回归分析表明，可以基于两个MF参数预测纤维类型组成。发现肌肉纤维CSA的加权测量值与初始MF和CV均呈线性相关。本研究结果表明，肌肉收缩期间记录的MF和CV参数与肌肉纤维类型组成和肌肉纤维CSA有关。
