Role of cocontraction in arm movement accuracy
Role of cocontraction in arm movement accuracy
复制标题
DOI：
10.1152/jn.01020.2002
复制
发表时间：
2003-05-01
影响因子：
2.5
通讯作者：
Mattar, A
中科院分区：
文献类型：
--
作者：
Gribble, PL;Mullin, LI;Mattar, A
共收缩（关节周围拮抗肌的同时激活）为神经系统提供了一种方法，使肢体的机械特性适应不断变化的任务要求-无论是在静态还是在运动中。然而，相对知之甚少的条件下，运动系统调制肢体阻抗通过cocontraction。本研究的目的是测试在多关节肢体运动中共收缩和运动准确性之间的可能关系。7个单关节和双关节的肩和肘肌肉的肌电图活动记录使用表面电极，而受试者在水平面上进行指向任务的目标，随机变化的大小。通过逐个试验为受试者提供反馈来控制移动速度。在运动过程中和运动结束后立即在200毫秒的窗口内估计cocontraction的措施。我们观察到目标大小和共收缩之间的反比关系：随着目标大小的减少，共收缩活动增加。此外，轨迹变异性降低，终点准确性提高。这表明，虽然能量昂贵，cocontraction可能是一种策略所使用的电机系统，以促进多关节手臂运动的准确性。我们还观察到共收缩水平随时间降低的总体趋势，支持共收缩和相关肢体僵硬在实践过程中减少的想法。
Cocontraction ( the simultaneous activation of antagonist muscles around a joint) provides the nervous system with a way to adapt the mechanical properties of the limb to changing task requirements - both in statics and during movement. However, relatively little is known about the conditions under which the motor system modulates limb impedance through cocontraction. The goal of this study was to test for a possible relationship between cocontraction and movement accuracy in multi-joint limb movements. The electromyographic activity of seven single- and double-joint shoulder and elbow muscles was recorded using surface electrodes while subjects performed a pointing task in a horizontal plane to targets that varied randomly in size. Movement speed was controlled by providing subjects with feedback on a trial-to-trial basis. Measures of cocontraction were estimated both during movement and during a 200-ms window immediately following movement end. We observed an inverse relationship between target size and cocontraction: as target size was reduced, cocontraction activity increased. In addition, trajectory variability decreased and endpoint accuracy improved. This suggests that, although energetically expensive, cocontraction may be a strategy used by the motor system to facilitate multi-joint arm movement accuracy. We also observed a general trend for cocontraction levels to decrease over time, supporting the idea that cocontraction and associated limb stiffness are reduced over the course of practice.