Lower Quadriceps Rate of Force Development Is Associated With Worsening Physical Function in Adults With or at Risk...

To determine the association between quadriceps rate of force development (RFD) and decline in self-reported physical function and objective measures of physical performance.

Longitudinal cohort study.

Community-based sample from 4 urban areas.

Osteoarthritis Initiative participants with or at risk for knee osteoarthritis, who had no history of knee/hip replacement, knee injury, or rheumatoid arthritis (N=2630).

Not applicable.

Quadriceps RFD (N/s) was measured during isometric strength testing. Worsening physical function was defined as the minimal clinically important difference for worsening self-reported Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale score, 20-m walk time, and repeated chair stand time over 36 months.

Compared with the slowest tertile of RFD, the fastest tertile had a lower risk for worsening of WOMAC physical function subscale score at 36-month follow-up, with an odds ratio (OR) of .68 (95% confidence interval [CI], .51-.92) after adjustment for age, sex, body mass index, depression, history of chronic diseases, and knee pain. In women, in comparison with the slowest tertile of RFD, the fastest tertile had a lower risk for worsening of WOMAC physical function subscale score at 36-month follow-up, with an adjusted OR of .57 (95% CI, .38-.86). This decreased risk did not reach statistical significance in men (OR, 0.81; 95% CI, 0.52-1.27). No statistically significant associations were detected between baseline RFD and walk or chair stand times.

Our results indicate that higher RFD is associated with decreased risk for worsening self-reported physical function but not with decreased risk for worsening of physical performance.