Effectiveness of three modes of kinetic-chain exercises on quadriceps muscle strength and thigh girth among individuals with knee osteoarthritis

Background The study was designed to evaluate and compare the effectiveness of 12-week open, closed and combined kinetic-chain exercises (OKCE, CKCE and CCE) on quadriceps muscle strength and thigh girth of patients with knee osteoarthritis (OA). Method The randomized clinical trial involved ninety-six consecutive patients with knee OA who were randomly assigned to one of OKCE, CKCE or CCE groups. Participants' static quadriceps muscle strength (SQS), dynamic quadriceps muscle strength (DQS) and thigh girth (TG) were assessed using cable tensiometer, one repetition method and inelastic tape measure respectively at baseline and at the end of weeks 4, 8 and 12 of study. Results The three groups were comparable regarding their demographic and dependent variables at baseline; there was significant time effect (p < 0.001each) as all three measures significantly increased over time from baseline to week 12 [mean difference: SQS: 3.30 (95% CI: 2.52-4.08) N; DQS: 0.74 (95% CI: 0.45-1.02) N; TG: 1.32 (95% CI: 0.93-1.71) cm]. The effect of intervention-time interaction was not significant (p > 0.05) for all three measures. Changes in SQS, DQS and TG between baseline and week 12 were also not significantly different (p > 0.05) among the three groups. Conclusion All three exercise regimens are effective and demonstrate similar effects on quadriceps muscle strength and muscular trophism. Trial registration NHREC/05/01/2008a. Registered 20th March, 2014 Retrospectively.