Article

Functional base of support (FBOS), the effective area for center of pressure
(COP) movement, decreases with aging, which would reduce one's ability to restore
balance during perturbed stance. We investigated the relationship between ankle
muscle strength and FBOS as well as the threshold perturbation acceleration that
required a heel-rise (HR) or step (STEP) to maintain balance. Standing posture of
16 young and 16 elderly adults was perturbed with a backward support surface
translation with the speed ranging from 15 to 70 cm/s. Dorsiflexor (DF) strength
was found to significantly correlate with FBOS measures and threshold
acceleration for HR. Significant correlations were also found between FBOS
measures and threshold accelerations for HR and STEP, except for the backward
FBOS and threshold acceleration for STEP. Elderly subjects demonstrated
significantly smaller DF strength and FBOS measures than young subjects, but no
significant group difference was detected in plantarflexor (PF) strength. Most
elderly subjects took a step once they raised their heels, while most young
subjects were able to restore balance after heel-rise. These findings, taken
together, imply that weakness in ankle dorsiflexors could limit the ability of
elderly adults to restore balance while standing on their toes. FBOS measures and
ankle dorsiflexor strength could be sensitive measures to detect individuals with
declined balance control.
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Langue : ANGLAIS