Man-Machine-Systems Group, Delft University of Technology, Department of Mechanical Engineering & Marine Technology, Mekelweg 2, 2628-CD Delft, The Netherlands.
J Electromyogr Kinesiol. 1993;3(2):112-22. doi: 10.1016/1050-6411(93)90006-I.
Goal-directed shoulder-elbow movements with a maximal and with a submaximal velocity have been studied. At the movement onset the inertial load to be displaced was changed unexpectedly. The adaptation of movement and muscular activity have been described with a moving average model. Significant adaptation effects were demonstrated in the first two or three movements after a change of mass. Adaptation only partly compensated the mass effects: A higher mass led to a persistent reduction of movement velocity. Amplitudes of muscular activity showed no adaptation of muscular effort, but activation durations were strongly modified. Thus the hypothesis that adaptation pursues a certain movement trajectory as a function of time had to be rejected. However, after scaling towards peak velocity, a shape invariance was demonstrated in the movement trajectory. In the first moyements after a change of mass, effective and substantial modifications of muscular activity appeared about 90 ms after movement onset. Earlier modifications suggest a force feedback leading to a yielding towards the disturbance instead of a compensation. Such force feedback may, however, increase system bandwidth as it will allow increased position/velocity feedback gains.
已经研究了具有最大和亚最大速度的目标导向肩肘运动。在运动开始时，意外地改变了要移动的惯性负载。使用移动平均模型描述了运动和肌肉活动的适应。在质量变化后的前两到三个运动中，观察到了明显的适应效果。适应仅部分补偿了质量效应：更高的质量导致运动速度持续降低。肌肉活动的幅度没有显示出肌肉努力的适应，但激活持续时间受到强烈的影响。因此，必须拒绝适应根据时间追求特定运动轨迹的假设。然而，在朝着峰值速度缩放后，运动轨迹表现出形状不变性。在质量变化后的第一个运动中，在运动开始后约 90 毫秒出现了有效的和实质性的肌肉活动的修改。较早的修改表明力反馈导致屈服于干扰而不是补偿。这种力反馈可能会增加系统带宽，因为它将允许增加位置/速度反馈增益。
