Article

To examine the age-related deterioration in postural control, we investigated the
association between postural sway during quiet standing and either amplitude of
physiological tremor or muscle volume of the plantar flexors in 20 young and 20
elderly adults. They maintained a quiet standing position on a force platform for
60s with their eyes open or closed. During quiet standing, physiological tremors
detected using a piezoresistive accelerometer were recorded from the soleus
muscle, and the center of pressure (COP) displacement and body acceleration in
the antero-posterior direction were calculated using the ground reaction forces
as an assessment of postural sway. Muscle volume was predicted from muscle
thickness by an ultrasonographic image. The physiological tremor of the soleus
muscle during quiet standing was significantly greater in elderly than in young
adults, and a positive association between physiological tremor and the amplitude
of postural sway was found for young and elderly adults combined. Furthermore,
physiological tremor was positively correlated with the high-frequency component
of COP sway during quiet standing. A significantly negative relation between the
muscle volume of the plantar flexors and postural sway was found in both age
groups. These results suggest that physiological tremor reflects high-frequency
fluctuations in postural sway during quiet standing in young and elderly adults,
and age-related increases in the postural sway amplitude in the antero-posterior
direction may be related to a decrease in muscle volume of the plantar flexors
for maintaining an upright posture.
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Langue : ANGLAIS