1045 - Higher Knee Extensor Power Linked to Lower Risk of Functional Worsening Over 24 Months in the MOST Study

In 1,641 adults (924 women, 717 men; mean age 61±9) from the Multicenter Osteoarthritis Study, KE power and strength were assessed. We evaluated 24-month WOMAC functional worsening (self-reported) and slowing of chair stand and 20-meter walk times. Sex-stratified linear regression was used for continuous chair-stand and 20-meter-walk times and logistic regression for dichotomous WOMAC worsening. Likelihood-ratio tests were used to determine whether adding KE power or strength meaningfully improved the model’s ability to explain each outcome. Regression coefficients were used to evaluate the size and direction of effect. Models included age, BMI, race, study site, CES-D score, and baseline values of each outcome.

Results:

Adding KE power significantly improved model fit for chair-stand and walking outcomes (p< 0.01), whereas adding strength did not (p >0.05). Although most participants chair stand and 20-meter-walk times increased at 24-month follow-up compared to baseline, those with higher KE power increased to a lesser degree. Specifically, a 1-SD higher baseline power was associated with 1.1 seconds less worsening in chair stand time in women (95% CI: –1.4, –0.8) and 0.7 seconds less worsening in men (–0.9, –0.5). Women had 0.3 seconds less worsening in walking speed (–0.5, –0.1), while men did not differ. For WOMAC functional worsening, neither predictor significantly improved model fit.

Conclusions: KE power predicted 2-year worsening of physical performance in men and women with knee osteoarthritis, while strength did not. These longitudinal findings suggest that, rather than strength, muscle power may be more important in functional decline.