Age-related changes in postural responses to externally- and self-triggered continuous perturbations

Abstract

This is a cross sectional study of eight healthy young (age 22 ± 2 years) and eight healthy older (age 70 ± 5 years) adults who participated in an experiment in which they had to keep their balance while standing on a platform moving in the anterior/posterior direction. The 20 cm peak-to-peak platform movements were sinusoidal at increasing frequencies up to 0.61 Hz. The frequency increases were either sudden and unpredictable (externally-triggered perturbations) or controlled by the subjects themselves (self-triggered perturbations). To maintain balance, all subjects used anticipatory adjustments such as early postural muscle activation, leading to fewer steps being taken, tighter coupling of the center of pressure (COP) and the platform movements, and small COP excursions. These adjustments were found to be lacking for externally-triggered perturbations in older subjects; in these subjects the COP range was larger and more often in less safe regions at the boundaries of the base of support. © 2005 Elsevier Ireland Ltd. All rights reserved.

Document Type

Article

Publication Date

1-1-2006

Publication Title

Archives of Gerontology and Geriatrics

ISSN

0167-4943

Volume

42

Issue

1

DOI

10.1016/J.ARCHGER.2005.05.003

First Page

73

Last Page

89

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