Training Modes Three training modes were chosen. (Ⅰ) SP (or called angled leg presses); (Ⅱ) KLCIR; (Ⅲ) KLC. The training phase had been lasting for 6 weeks in which none dropped out. Each subject had to accomplish three training workouts weekly under supervision by licensed athletic trainers. A workout contained five sets for each lower limb, which were composed of 20 (repetitions)×60% (1RM), 15×65% , 12×70% , 8×75% and 20×60% with a two-minute resting interval between each set. During the six-week rehabilitation course, they were not allowed to involve in any other regular fitness activities or sports.