Department of Anatomy, University of Manitoba, 730 William Avenue, Winnipeg, Manitoba, Canada, R3E 0W3; Physiotherapy Adult Services, Health Sciences Centre, 800 Sherbrook Street, Winnipeg, Manitoba, Canada, R3A 1R9.
J Electromyogr Kinesiol. 1993;3(2):78-86. doi: 10.1016/1050-6411(93)90002-E.
Electromyography (EMG) was used to study the role of antagonist cocontration of the hamstring muscles of 24 normal subjects during constant velocity muscle performance tests on a KIN COM (™) dynamometer. The hypothesis tests whether antagonist cocontraction varies dependent on joint angle, limb velocity, and type of contraction. Seated subjects performed two dynamic tests of resisted quadriceps muscle shortening and lengthening through a 65° range of knee motion under two constant velocity conditions in a single session. Each test consisted of four repetitions of maximum effort constant velocity muscle shortening and lengthening of the knee extensors; one test performed at 30° s(-1), the other at 90° s(-1). The sequence of velocity testing was randomized. Normalized values of peak amplitude EMG of knee flexors were measured every 5° in the constant velocity phase of each test and compared in a paired manner between each angle, contraction type, and velocity, by split-plot 2-way ANOVA. Antagonist hamstrings cocontraction was found to be contraction type, and velocity dependent. Cocontraction was greater at larger angles of knee flexion and at higher velocity. These results do not support the hypothesis that such activity is a function of muscle moment-arm, but are consistent with the idea that antagonist muscle function is controlled by muscle spindles and perhaps Golgi tendon organs. Because antagonist cocontraction ranged up to a mean of 32% of maximum agonist activity in normal individuals, it should be taken into consideration when interpreting clinical muscle performance tests.
肌电图（EMG）用于研究 24 名正常受试者在 KIN COM（™）测力计上进行恒速肌肉性能测试时，腘绳肌拮抗肌协同收缩的作用。该假设检验拮抗肌协同收缩是否依赖于关节角度、肢体速度和收缩类型而变化。坐姿受试者在单次测试中以两种恒速条件下进行 65°膝关节运动范围内的股四头肌缩短和伸展的两种动态测试。每个测试由四个最大努力的重复组成，即膝关节伸肌的恒速肌肉缩短和伸展；一个在 30° s（-1）下进行，另一个在 90° s（-1）下进行。速度测试的顺序是随机的。在每个测试的恒速阶段，每隔 5°测量膝关节屈肌的峰振幅 EMG 的归一化值，并通过两因素随机区组方差分析以配对方式在每个角度、收缩类型和速度之间进行比较。拮抗肌腘绳肌协同收缩是收缩类型和速度的依赖性。在更大的膝关节弯曲角度和更高的速度下，协同收缩更大。这些结果不支持这种活动是肌肉力臂函数的假设，而是与拮抗肌功能受肌梭和可能的高尔基腱器官控制的观点一致。由于拮抗肌协同收缩在正常个体中最高可达最大激动剂活动的 32%，因此在解释临床肌肉性能测试时应考虑到这一点。
