The effect of dynamic versus isometric resistance training on pain and functioning among adults with osteoarthritis of the knee

Objective: To compare 16 weeks of isometric versus dynamic resistance training versus a control on knee pain an functioning among patients with knee osteoarthritis (OA). Design: Randomized clinical trial. Setting: Outpatient setting. Participants: A total of 102 volunteer subjects with OA of the knee randomized to isometric (n=32) and dynamic (n=35) resistance training groups or a control (n=35). Interventions: Strength exercises for the legs,3 times weekly for 16 weeks. Dynamic group: exercises across a functional range of motion; isometric: exercises at discrete joint angles. Main Outcome Measures: The time to descend and ascend a flight of 27 stairs and to get down and up off of the floor. Knee pain was assessed immediately after each functional task. The Western Ontario and McMaster Universities Osteoarthritis Index was used to assess perceived pain, stiffness, and functional ability. Results: In the isometric group, time to perform all 4 functional tasks decreased (P<.05) by 16% to 23%. In the dynamic group, time to descend and ascend stairs decreased by 13% to 17%. Both groups decreased knee pain while performing the functional tasks by 28% to 58%. Other measures of pain and functioning were significantly and favorably affected in the training groups. The improvements in the 2 training groups as a result of their respective therapies were not significantly different. The control group did not change over the duration of the study. Conclusion: Dynamic or isometric resistance training improves functional ability and reduces knee joint pain of patients with knee OA.