Reaching upward is more challenging to dynamic balance than reaching forward.

摘要

BACKGROUND: Older adults have less confidence in their ability to reach upward compared to reaching forward. The forward reach test may, therefore, not be ideally suited for detecting functional deficits that directly affect daily activities. METHODS: A new test of upward reach and forward reach (along a 50-degree track) were administered to young and older adults. Reach distance was adjusted for foot length and normalized to stature. The anterior safety margin was calculated by relating the center of pressure to the base of support. The extent to which age, sex, balance confidence, anthropometric, and center of pressure parameters contribute to forward and upward reach performance was assessed. FINDINGS: Reach and anterior safety margin scores were well-correlated between forward and upward reaching, but the upward reach test posed a greater challenge to dynamic balance - eliciting a smaller anterior safety margin from both older and younger subjects. Further, compared to young adults, older adults showed greater limitations in reach distance and balance parameters during upward reach compared with forward reach. An observational measure of reach strategy (whether or not the heels were raised from the platform during the test) differentiated between higher and lower reach performance for older adults. Anthropometric variables accounted for much of the variance in reach performance that would otherwise have been attributed to an age-related loss of functional capacity. Balance confidence scores also contributed to regression models predicting upward - but not forward - reach performance in older adults. INTERPRETATION: Though upward and forward reach performances were well related in this sample, a test of upward reach may be better suited to reveal early signs of functional decline in older adults than a test of forward reach.