The contribution of leg press and knee extension strength and power to physical function in people with knee osteoarthritis: A cross-sectional study

A cross-sectional, exploratory study of 40 individuals with tibiofemoral knee osteoarthritis resulting in moderate impairments in physical function was conducted. Physical function (Get-up and Go, timed stair climb and descent, and five time chair rise) and muscle performance (leg press and knee extension strength and power) were assessed.

After controlling for covariates and strength, leg press, but not knee extensor, power explained additional variance in physical function (11% and 21%). Conversely, adding strength to regression models including covariates and power did not consistently improve the prediction of physical function. Additionally, leg press power consistently explained more variance in physical function (44 to 57%) than involved (24 to 34%) or uninvolved (28 to 48%) knee extension power.

Leg press power may be a more functionally relevant measure of muscle performance than knee extension strength in this population. Future studies should investigate the effectiveness of interventions specifically designed to improve leg press power in people with knee osteoarthritis.