Purpose : We examined the effect of therapeutic exercise on osteoarthritis (OA) of the knee. Objects and Method : We evaluated seven women with bilateral OA of the knees of over Grade I on the Kellgren and Lawrence scale. The patients were instructed in therapeutic exercise for both knees. The exercise was to tie a Thera-Band ^® around the leg just above both ankles in the 8 figure, and then, in a sitting position, extend one leg while simultaneously retracting the other, repeating alternatively every 5 seconds. One set consisted of repeating this motion 10 times, and 2 sets were performed per day. Before exercise, 1 month, and 3 months after exercise, we evaluated the effect of this therapy by the JOA score, isokinetic muscle strength of knee extensors and flexors, and surface EMG signals recorded from rectos femoris (RF), vastus medialis (VM), vastus lateralis (VL), and biceps lemons (BF) . The integrated signal, the root mean square (RMS), and the mean power frequency (MPF) parameters were extracted.
Result : The parameters of the JOA score, muscle strength of knee flexors, integrated EMG from RF, VM, VL, and RMS from VM, VL were significantly increased at 3 months after exercise. MPF from VM at 3 months after exercise decreased significantly.
Conclusion : We thought a proper balance of knee extensors and flexors are related to the improvement of symptoms of OA of the knee. The decrease of MPF might suggest the possibility of muscle fiber type change. It is also possible that pain reduction results from the improvement of balance between knee extensors and flexors as well as from the increase of knee joint stability. Therapeutic exercise with the Thera-Band R is extremely easy and is effective in promoting con-tinuous exercise.