Kempf T, Corcos D M, Flament D
Department of Physical Medicine and Rehabilitation, Rush-Presbyterian-St Luke's Medical Center, Chicago, IL 60612, USA.
Exp Brain Res. 2001 Feb;136(3):295-302. doi: 10.1007/s002210000584.
Learning a motor task is associated with specific changes in movement kinematics. Recently, it has been shown that changes in different kinematic parameters occurred with different time courses for subjects who practiced simple, single-joint elbow movements. For example, movement time was seen to decrease and level off in a shorter time than peak velocity, which increased and plateaued later. What is not known, however, is whether the time course and temporal order of these learning-related changes seen at the elbow are similar for movements learned at other joints and with different instructions. In this study, neurologically normal subjects practiced 50 degrees -flexion movements made at the wrist, with the instruction to be both "fast and accurate" (same instruction used in the earlier elbow study). A different group of subjects practiced wrist movements of the same amplitude, but with instructions to make movements that were "always accurate;" only as movement skill developed could subjects increase their speed (but without ever sacrificing accuracy). We measured time-related parameters (duration of acceleration, duration of deceleration, and total movement duration) and magnitude-related parameters (peak velocity, peak acceleration, and peak deceleration). We found that the time course of changes in kinematic parameters for subjects instructed to be "fast and accurate" was similar to that reported at the elbow. When the instruction was changed to be "always accurate," the time for changes in kinematic parameters to level off was found to be longer. However, regardless of instruction, time-related parameters plateaued before magnitude-related parameters. Thus, our results indicate that motor learning mechanisms may operate in a similar way at different joints.
学习一项运动任务与运动运动学的特定变化相关。最近的研究表明，对于练习简单的单关节肘部运动的受试者，不同运动学参数的变化具有不同的时间进程。例如，与峰值速度相比，运动时间在更短的时间内下降并趋于平稳，而峰值速度则在较晚的时候增加并趋于平稳。然而，尚不清楚的是，在肘部观察到的这些与学习相关的变化的时间进程和时间顺序，对于在其他关节进行的运动以及在不同指令下是否相似。在本研究中，神经功能正常的受试者练习手腕进行50度的屈曲运动，指令为“快速且准确”（与早期肘部研究中使用的指令相同）。另一组受试者练习相同幅度的手腕运动，但指令是做出“始终准确”的运动；只有随着运动技能的发展，受试者才能提高速度（但绝不牺牲准确性）。我们测量了与时间相关的参数（加速持续时间、减速持续时间和总运动持续时间）以及与幅度相关的参数（峰值速度、峰值加速度和峰值减速度）。我们发现，被指示“快速且准确”的受试者运动学参数变化的时间进程与肘部研究中报告的相似。当指令改为“始终准确”时，发现运动学参数趋于平稳的时间更长。然而，无论指令如何，与时间相关的参数在与幅度相关的参数之前趋于平稳。因此，我们的结果表明，运动学习机制在不同关节可能以类似的方式运作。
