Changes in the variability of movement trajectories with practice.
Changes in the variability of movement trajectories with practice.
复制标题
随着练习运动轨迹的可变性发生变化。
DOI：
10.1080/00222895.1987.10735414
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发表时间：
1987
影响因子：
1.4
通讯作者：
J. Cooke
中科院分区：
文献类型：
--
作者：
Warren G. Darling;J. Cooke
我们研究了运动过程中运动相平面轨迹（速度-位置关系）的变化性。人类受试者进行10度和30度肘关节屈曲和伸展运动中的视觉步跟踪范例。半径等于位置和速度的一个标准差的椭圆的面积被作为轨迹可变性的量度。在整个运动过程中，以10 ms的间隔测定轨迹变异性。运动的加速和减速阶段的轨迹变异性随着练习而降低。在减速过程中的平均轨迹变异性大于在加速过程中，即使经过延长的实践（1000次试验）。在练习过程中，受试者通常在保持末端位置准确性的同时提高运动速度。当给予等量的练习时，轨迹变异性也与运动速度有关。短持续时间（快速）运动有更大的轨迹变异性比长持续时间的运动。因此，在运动速度和轨迹可变性之间存在类似于经典的速度-精度权衡的权衡。在运动的加速阶段，轨迹变异性迅速增加。增加率与运动幅度和速度呈正相关。因此，产生肢体加速度的力是可变的，并且这种可变性在更快和更大的运动中更显着。与此相反，轨迹变化增加更慢，或实际上减少在运动的减速阶段。因此，肢体减速所涉及的力似乎或多或少地补偿了加速力的变化。实验表明，简单的肢体运动的整个轨迹是由中枢神经系统控制的。加速力的变化可以通过减速力的相关变化来补偿。加速力和减速力之间的联系随着练习而逐渐完善，从而降低了运动轨迹的可变性。
We studied variability in movement phase plane trajectories (velocity-position relation) during movement. Human subjects performed 10 degrees and 30 degrees elbow flexion and extension movements in a visual step tracking paradigm. The area of ellipses with radii equal to one standard deviation in position and velocity was taken as a measure of trajectory variability. Trajectory variability was determined at 10-ms intervals throughout movements. Trajectory variability in both the acceleration and deceleration phases of movement decreased with practice. The average trajectory variability during deceleration was greater than that during acceleration even after extended practice (1000 trials). During practice, subjects usually increased movement speed while maintaining end-position accuracy. Trajectory variability was also related to movement speed when equal amounts of practice were given. Short duration (fast) movements had greater trajectory variability than long duration movements. Thus there is a tradeoff between movement speed and trajectory variability similar to the classical speed-accuracy tradeoff. Trajectory variability increased rapidly during the acceleratory phase of movement. The rate of increase was positively related to both movement amplitude and speed. Thus, the forces producing limb acceleration were variable and this variability was more marked in faster and larger movements. In contrast, trajectory variability increased more slowly or actually decreased during the deceleratory phase of movements. Forces involved in limb deceleration thus appeared to compensate to a greater or lesser degree for the variability in accelerative forces. The experiments indicate that the entire trajectory of simple limb movements is controlled by the central nervous system. Variations in accelerative forces may be compensated for by associated variations in decelerative forces. The linkage between accelerative and decelerative forces is progressively refined with practice resulting in decreased variability of the movement trajectory.
影响因子：
2.5
作者：
GEORGOPOULOS, AP;KALASKA, JF;MASSEY, JT
通讯作者：
MASSEY, JT