Ma S P, Zahalak G I
J Biomech. 1985;18(8):585-98. doi: 10.1016/0021-9290(85)90013-2.
Very rapid, small amplitude, ramp-and-hold rotations were imposed on the braced forearms of three normal adult male subjects who were isometrically contracting their elbow extensors. By carefully accounting for inertial and viscoelastic coupling effects in the experimental system it was possible to compute the time course of the muscle-moment evoked by these mechanical perturbations. The muscle-moment responses, and their dependence on rotation amplitude and direction, as well as tonic contraction level, are described. These responses are also compared to the predictions of a simple muscle model which we have proposed previously on the basis of frequency-response tests. The results indicate that: at a given tonic contraction level, triceps may be stiffer in an isometric state than in an oscillatory steady state, and high frequency fluctuations in the myoelectric activity are very ineffective in generating corresponding muscle-force fluctuations.
对三名正常成年男性受试者的支撑前臂施加非常快速、小幅度的斜坡-保持旋转，此时他们正在等长收缩肘部伸肌。通过仔细考虑实验系统中的惯性和粘弹性耦合效应，可以计算出这些机械扰动诱发的肌肉力矩随时间的变化过程。描述了肌肉力矩响应及其对旋转幅度和方向以及强直收缩水平的依赖性。还将这些响应与我们之前基于频率响应测试提出的简单肌肉模型的预测进行了比较。结果表明：在给定的强直收缩水平下，三头肌在等长状态下可能比在振荡稳态下更僵硬，并且肌电活动中的高频波动在产生相应的肌肉力波动方面非常无效。
