Huang Min H, Brown Susan H
Physical Therapy Department, School of Health Professions and Studies, University of Michigan - Flint, United States.
Motor Control Laboratory, School of Kinesiology, University of Michigan, United States.
Gait Posture. 2015 Jan;41(1):276-81. doi: 10.1016/j.gaitpost.2014.10.018. Epub 2014 Oct 28.
Reaching is an important component of daily activities with goals to interact and acquire objects in the environment. The task context of reaching, as determined by the behavioral goal and the properties of the object, can influence the control of posture and movements. This study examined age differences in postural stability during a forward reach under two task contexts, grasping versus pointing to a target. Young and older participants living in the community performed the tasks from the standing position. They reached forward, grasped or pointed to a target, and then returned to an upright posture as fast as possible. Postural stability was analyzed using the center of pressure (COP) during two phases of the task: the reaching movement phase and the returning movement phase. In the grasping context, the COP path deviations were significantly larger in older compare to young participants during both the reach and the return movement phases. In addition, during the return movement phase, only older participants showed a context-dependent increase in COP path deviations after grasping compared to pointing. The results highlight the impact of task context on postural stability during standing reach in young and older adults. Interventions for older adults with balance problems should consider incorporating activities that involve the interaction with objects of various properties in the environment. Future studies are necessary to investigate the factors underlying the person-environment interplay of postural control and the adaptation of anticipatory postural control associated with object interaction during functional tasks in older adults.
伸手够物是日常活动的重要组成部分，其目的是在环境中进行互动和获取物体。伸手够物的任务情境，由行为目标和物体属性决定，会影响姿势和动作的控制。本研究考察了在两种任务情境下（抓握目标与指向目标）向前伸手时姿势稳定性的年龄差异。居住在社区的年轻和年长参与者从站立姿势开始执行任务。他们向前伸手，抓握或指向一个目标，然后尽快恢复到直立姿势。在任务的两个阶段（伸手动作阶段和返回动作阶段），使用压力中心（COP）分析姿势稳定性。在抓握情境中，年长参与者在伸手和返回动作阶段的COP路径偏差均显著大于年轻参与者。此外，在返回动作阶段，与指向目标相比，只有年长参与者在抓握后表现出COP路径偏差随情境的增加。结果突出了任务情境对年轻人和年长者站立伸手时姿势稳定性的影响。针对有平衡问题的年长者的干预措施应考虑纳入涉及与环境中各种属性物体进行互动的活动。未来有必要开展研究，以调查年长者在功能任务中姿势控制的人与环境相互作用以及与物体互动相关的预期姿势控制适应背后的因素。
