Article

Reaching tasks are commonly performed during daily activities and require
anticipatory postural adjustments (APAs) to ensure a stable posture during
movement execution. Age-related changes in APAs may impact dynamic balance and
cause postural instability during reaching tasks made from standing. The present
study examined age differences in postural control during reaching to targets
located at different heights. Fourteen young adults (aged 20.0+/-1.5 yrs) and 16
community-dwelling older adults (aged 73.4+/-5.3 yrs) participated in the study.
The task involved reaching forward to grasp a cylinder, and returning to an
upright position as fast and accurately as possible. Postural control was
analyzed using the center of pressure (COP) during four phases of the task: COP
displacement during APA production, COP trajectory smoothness during the reach
and return phases, and COP path length during the recovery phase following
movement. APA amplitude measured by COP displacement and COP path length during
the recovery phase was larger in older compared to young adults. Dynamic balance
represented by COP trajectory smoothness was reduced with age. In both age
groups, APA amplitude was largest and COP trajectory smoothness the least during
low target reaches. The results demonstrate that, while older adults can alter
APAs in order to maintain postural stability, control of COP during movement
execution, particularly during low target reaches, is compromised with aging.
These findings have clinical implications for both the assessment of dynamic
balance and the development of balance training programs.
CI - Copyright (c) 2013 Elsevier B.V. All rights reserved.

Langue : ANGLAIS