The journals of gerontology. Series A, Biological sciences and medical sciences
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J. Gerontol. A Biol. Sci. Med. Sci. · Feb 2004
Comparative StudyAging-induced shifts from a reliance on sensory input to muscle cocontraction during balanced standing.
Peripheral sensation is the most important sensory system in the maintenance of upright posture in all age groups. With aging, visual and somatosensory processing change their prospective contribution to the maintenance of quiet standing, at debated percentages. Aging is associated with a decrease in balance abilities that, in turn, increases the risk of falling. We used force plate data to show that, with aging, while vision plays a significant role in regulating postural stability (PS), the individual's perception of his/her stability becomes more significant than vision. Moreover, under experimental conditions, electromyography (EMG) of the ankle musculature of elderly people reveals the adoption of a different strategy, a cocontraction strategy, with or without visual input. The aim of this study was to look at two distinct age groups to determine whether or not a shift takes place in the sensory modality typically relied on while maintaining PS during a static, postural-related task. ⋯ To cope with the deterioration in their sensory input and processing ability, elderly individuals seemed to have developed a strategy of stiffening and freezing their lower legs during upright standing.