Division of Sport and Recreation, University of Northumbria at Newcastle, Newcastle upon Tyne, NE1 8ST, U.K.
J Electromyogr Kinesiol. 1996 Dec;6(4):235-45. doi: 10.1016/s1050-6411(96)00012-0.
The purpose of this study was to compare different normalization methods of electromyographic (EMG) activity of antagonists during isokinetic eccentric and concentric knee movements. Twelve women performed three maximum knee extensions and flexions isometrically and at isokinetic concentric and eccentric angular velocities of 30 degrees .s(-1), 90 degrees .s(-1), 120 degrees .s(-1) and 150 degrees .s(-1). The EMG activity of the vastus lateralis, rectus femoris, vastus medialis and hamstrings was recorded. The antagonist integrated IEMG values were normalized relative to the EMG of the same muscle during an isometric maximal action (static method). The values were also expressed as a percentage of the EMG activity of the same muscle, at the same angle, angular velocity and muscle action (dynamic method) when the muscle was acting as an agonist. Three-way analysis of variance (ANOVA) designs indicated significantly greater IEMG normalized with the dynamic method compared to the EMG derived using the static method (P < 0.05). These differences were more evident at concentric angular velocities and at the first and last 20 degrees of the movement. The present findings demonstrate that the method of normalization significantly influences the conclusions on antagonistic activity during isokinetic maximum voluntary efforts. The dynamic method of normalization is more appropriate because it considers the effects of muscle action, muscle length and angular velocity on antagonist IEMG.
本研究旨在比较等速向心和离心运动中拮抗肌肌电图（EMG）活动的不同归一化方法。12 名女性进行了 3 次最大等长膝关节伸展和屈曲，以及 30°·s^(-1)、90°·s^(-1)、120°·s^(-1)和 150°·s^(-1)的等速向心和离心运动。记录了股外侧肌、股直肌、股内侧肌和腘绳肌的 EMG 活动。将拮抗肌的积分 IEMG 值相对于等长最大动作时同一肌肉的 EMG 进行归一化（静态方法）。还以相同肌肉在相同角度、角速度和肌肉作用时（动态方法）的 EMG 活动的百分比表示，当肌肉作为主动肌时。三因素方差分析（ANOVA）设计表明，与静态方法相比，动态方法归一化的 IEMG 值显著更高（P<0.05）。在向心角速度和运动的前 20 度和最后 20 度时，这些差异更为明显。本研究结果表明，归一化方法显著影响等速最大自主努力时拮抗活动的结论。动态归一化方法更为合适，因为它考虑了肌肉作用、肌肉长度和角速度对拮抗肌 IEMG 的影响。
