The purpose of this study was to assess the effect of the rehabilitation program using MERAC after surgery on future injury prevention. The subjects in this study were two injured university elite athletes. One was a male volleyball player and another was a female tennis player. They had ruptured cartilage on the right knee. The 8-weeks rehabilitation program in this study was designed using isokinetic muscle contraction exercise in order to rehabilitate strength of knee joint. The following results were obtained 1. Mean power with the high speed loading rehabilitated the most rapidly in the rehabilitation. program. 2. The femoral extensor strength showed faster recovery than the femoral flexor strength did during the rehabilitation program. 3. With the low speed loading the recovery was faster in maximal strength than in mean power, while with the high speed loading the recovery was faster in mean power than in maximal strength. 4. The muscle wavers in maximal strength exertion improved and finally disappeared during the rehabilitation program. 5. Following the rehabilitation program, the strength of femoral muscles, except mean power, rehabilitated to a normal range.