Abstract
OBJECTIVE: To determine which lower limb strength and joint kinetic and kinematic parameters distinguish sit-to-stand (STS) performance of older adults with symptomatic knee osteoarthritis (OA) with higher and lower chair stand time. DESIGN: Cross-sectional. SETTING: Motion analysis laboratory. PARTICIPANTS: Individuals (N=49; 26 men, 23 women) aged 50 to 79 years (mean ± SD age, 64.7±8.1y) with radiographic knee OA and daily symptoms, stratified by chair stand times. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Lower limb strength and STS strategy. RESULTS: The chair stand times (mean ± SD) in the high-, moderate-, and low-functioning groups in men were 6.5±0.7, 8.6±0.7, and 11.5±1.3 seconds, respectively, and in women were 7.6±1.2, 10.0±0.5, and 12.8±1.8 seconds, respectively. Chair stand time (P=.0391) and all measures of lower limb strength (all P<.0001) differed by sex. In men, no strength measure differed between groups, whereas in women hip abductor strength on the more affected side differed between groups. In men, sagittal hip range of motion (ROM) (P=.0122) differed between groups, and there was a trend toward a difference in sagittal knee power (P=.0501) during STS, while in women only sagittal knee ROM (P=.0392) differed between groups. CONCLUSIONS: Higher- and lower-functioning adults with symptomatic knee OA appear to use different strategies when standing from a chair. Higher-functioning men flexed more at the hip and produced greater knee power than lower-functioning men. Higher-functioning women used less knee flexion than lower-functioning women. Since STS is an important mobility task, these parameters may serve as foci for rehabilitation aimed at reducing mobility limitations.