Exploring the relationship between the maximal rate of force development of ankle muscles and the functional ability of patients with knee osteoarthritis

Background and study aims The impairment of the knee muscles brought on by knee osteoarthritis alters motor function, lowers levels of physical activity, and raises the risk of falling. This study aimed to assess ankle muscle function in individuals with mild to moderate knee osteoarthritis compared to a control group. Specifically, maximal rate of force development in dorsiflexor and plantar flexor muscles, along with the ankle dorsi/plantar ratio, were examined. Additionally, the relationship between rate of force development and functional measures in knee osteoarthritis patients was investigated. Materials and methods A total of 126 participants aged 30 to 45 were divided into knee osteoarthritis and control groups. The Biodex System 4 isokinetic dynamometer assessed rate of force development of ankle muscles at various speeds, encompassing dynamic contractions at 60°/s and 120°/s, as well as isometric measurements. The dorsi/plantar ratio was calculated at the same speeds. Subjective evaluation employed the Knee Injury and Osteoarthritis Outcome Score, while functional measures included the Forward Step-Down Test and Single-Leg Hop Test to establish the correlations with rate of force development and the dorsi/plantar ratio. Results The knee osteoarthritis group exhibited significantly higher rate of force development for both ankle plantar flexors during dynamic contractions at 60°/s and 120°/s, which was observed bilaterally in the knee osteoarthritis group (p