University of Wisconsin-Madison.
Motor Control. 2020 Jan 1;24(1):57-74. doi: 10.1123/mc.2018-0053.
Reaching and grasping are often completed while walking, yet the interlimb coordination required for such a combined task is not fully understood. Previous studies have produced contradictory evidence regarding preference for support of the lower limb ipsilateral or contralateral to the upper limb when performing a reaching task. This coordinative aspect of the combined task provides insight into whether the two tasks are mutually modified or if the reach is superimposed upon normal arm swinging. Collectively, 18 right-handed young adults walked slower, took shorter steps, and spent more time in double support during the combined task compared with walking alone. The peak grasp aperture was larger in walking reach-to-grasp trials compared with standing trials. There was not a strong trend for lower limb support preferences at the reach initiation or object contact. The participants could begin walking with either foot and demonstrated variability of preferred gait initiation patterns. There was a range of interlimb coordination patterns, none of which could be generalized to all young adults. The variability with which healthy right-handed young adults execute a combined walking reach-to-grasp task suggests that the cyclical (walking) and discrete (prehension) motor tasks may have separate motor control mechanisms, as proposed in the two primitives theory.
行走时通常会同时进行伸手和抓握动作，但对于这种组合任务所需的肢体间协调性还不完全清楚。之前的研究对于在进行伸手任务时，上肢同侧或对侧下肢的支撑偏好，得出了相互矛盾的证据。组合任务的这种协调方面可以深入了解两个任务是否相互改变，或者伸手动作是否叠加在正常的手臂摆动上。总体而言，与单独行走相比，18 名右利手的年轻人在组合任务中行走速度较慢、步伐较短且双支撑时间更长。与站立试验相比，行走伸手抓握试验的最大抓握开口更大。在伸手开始或物体接触时，下肢支撑偏好没有明显的趋势。参与者可以用任意一只脚开始行走，并表现出不同的起始步态模式偏好。存在一系列肢体间协调模式，没有一种模式可以推广到所有年轻人。健康的右利手年轻人执行组合行走伸手抓握任务的方式存在很大的变异性，这表明循环（行走）和离散（抓握）运动任务可能具有单独的运动控制机制，这与两原动器理论的观点一致。
