van Zandwijk J P, Bobbert M F, Harlaar J, Hof A L
Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
Biol Cybern. 1998 Aug;79(2):121-30. doi: 10.1007/s004220050464.
In models describing the excitation of muscle by the central nervous system, it is often assumed that excitation during a tetanic contraction can be obtained by the linear summation of responses to individual stimuli, from which the active state of the muscle is calculated. We investigate here the extent to which such a model describes the excitation of human muscle in vivo. For this purpose, experiments were performed on the calf muscles of four healthy subjects. Values of parameters in the model describing the behaviour of the contractile element (CE) and the series elastic element (SEE) of this muscle group were derived on the basis of a set of isokinetic release contractions performed on a special-purpose dynamometer as well as on the basis of morphological data. Parameter values describing the excitation of the calf muscles were optimized such that the model correctly predicted plantar flexion moment histories in an isometric twitch, elicited by stimulation of the tibial nerve. For all subjects, the model using these muscle parameters was able to make reasonable predictions of isometric moment histories at higher stimulation frequencies. These results suggest that the linear summation of responses to individual stimuli can indeed give an adequate description of the process of human muscle excitation in vivo.
在描述中枢神经系统对肌肉的兴奋作用的模型中，通常假定强直收缩期间的兴奋可通过对单个刺激的反应进行线性叠加得到，据此计算肌肉的激活状态。我们在此研究这样一个模型在多大程度上描述了人体肌肉在体内的兴奋情况。为此，对四名健康受试者的小腿肌肉进行了实验。描述该肌群收缩元件（CE）和串联弹性元件（SEE）行为的模型参数值，是基于在专用测力计上进行的一组等速释放收缩以及形态学数据得出的。描述小腿肌肉兴奋的参数值经过优化，以使该模型能正确预测由刺激胫神经引发的等长单收缩中的跖屈力矩历程。对于所有受试者，使用这些肌肉参数的模型能够对较高刺激频率下的等长力矩历程做出合理预测。这些结果表明，对单个刺激的反应进行线性叠加确实能够充分描述人体肌肉在体内的兴奋过程。
