Strengthening Exercise and Quadriceps Force During Walking

This is a longitudinal, randomized, controlled interventional multi centric study on the effects of lower leg strengthening exercise on quadriceps force during walking in people with knee osteoarthritis. At each study centre twenty subjects will be included, for a total of 40 participants. Subjects will be randomized equally (1:1) into 1 active arm and 1 control arm. The objective of the study is to evaluate the effect of twelve weeks of quadriceps strengthening on the mechanical output of the quadriceps during locomotion. A secondary purpose is to explore the relationship between quadriceps strengthening and compressive knee loadings. The hypothesis is that quadriceps strength training will not change quadriceps force, power, and work in locomotion in people with knee osteoarthritis. Primary outcome is quadriceps force during walking, secondary outputs are quadriceps power and work and knee compressive loads during walking. Explorative measures are isometric and concentric isokinetic leg muscle strength, radiographic score of the knee (Kellgren and Lawrence), a one-leg rise from chair test (maximum number of reps) and a lateral step-up test (maximum number of reps).