Latash M L, Gottlieb G L
Department of Physical Medicine and Rehabilitation, Rush Medical College, 1753 West Congress Parkway, Chicago, IL 60612, USA.
J Mot Behav. 1991 Sep;23(3):179-91. doi: 10.1080/00222895.1991.10118361.
The model for isotonic movements introduced in the preceding article in this issue is used to account for isometric contractions. Isotonic movements and isometric contractions are analyzed as consequences of one motor program acting under different peripheral conditions. Differences in isotonic and isometric EMG patterns are analyzed theoretically. Computer simulation of the EMG patterns was performed both with and without the inclusion of possible effects of reciprocal inhibition. A series of experiments was performed to test the model. The subjects made fast isotonic movements that were unexpectedly blocked at the very beginning in some of the trials. The observed differences in the EMG patterns between blocked and unblocked trials corresponded to the model's predictions. The results suggest that these differences are due to the action of a tonic stretch reflex rather than to preprogrammed reactions. The experimental and simulation findings, and also the data from the literature, are discussed in the framework of the model and the dual-strategy hypothesis. They support the hypothesis that the motor control system uses one of a few standardized subprograms, specifying a small number of parameters to match a specific task.
本期前一篇文章中介绍的等张运动模型被用于解释等长收缩。等张运动和等长收缩被分析为一个运动程序在不同外周条件下作用的结果。从理论上分析了等张和等长肌电图模式的差异。在包含和不包含交互抑制可能影响的情况下，都对等长肌电图模式进行了计算机模拟。进行了一系列实验来测试该模型。受试者进行快速等张运动，在某些试验中运动在刚开始时意外受阻。观察到的受阻试验和未受阻试验之间肌电图模式的差异与模型预测相符。结果表明，这些差异是由于紧张性牵张反射的作用，而非预编程反应。在该模型和双策略假说的框架内，对实验和模拟结果以及文献数据进行了讨论。它们支持这样一种假说，即运动控制系统使用少数几个标准化子程序之一，指定少量参数以匹配特定任务。
