Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 53, Issue 4 M320-M326, Copyright © 1998 by The Gerontological Society of America
The relation between age-related changes in neuromusculoskeletal system and dynamic postural responses to balance disturbance
G Wu
Department of Physical Therapy, University of Vermont, Burlington.
BACKGROUND: The purpose of this study was to identify some critical factors
whose functional changes with age in the neuromusculoskeletal systems would
potentially relate to the maintenance of standing balance. METHODS: A
total of 38 healthy subjects were tested (age range, 21-77 years). A
postural disturbance at the foot was provided, and the range of movement of
the head, trunk, thigh, shank, and foot was examined. Three supporting
surfaces were tested: hard, soft, and reduced. The functions evaluated in
each subject included general health, touch, and cutaneous vibratory
perception threshold at four different locations, ankle strength, and range
of motion. The functions were then correlated with the maximum magnitude of
the body movement. RESULTS: There were significant age-related changes in
cutaneous vibratory perception threshold at all four locations of the foot,
in platarflexor strength, and in touch sensation at the heel region. Age
had a positive correlation with head movement regardless of the supporting
surface and the movement direction of the platform. Plantarflexor strength
was also correlated with head movement but only when the platform moved in
the backward direction. When standing on a large supporting base the
change in cutaneous vibratory perception threshold at the 5th metatarsal
head with respect to age showed a larger, although weak, effect on the head
moevement than the cutaneous vibratory peception threshold at other
regions. CONCLUSIONS: The stabilization of an upright balance, especially
the head, was related to age, plantarflexor strength, and vibratory
perception at the foot. The laboratory test in this study identified such
correlations.
