Thirty-two patients undergoing anterior cruciate ligament reconstruction were randomized to receive blood flow restriction therapy in combination with low-load resistance (n=17) or standard rehabilitation (n=15). The primary outcome of this trial was to determine changes in bone and muscle mass from presurgery to 6 and 12 weeks post-operatively. Secondary outcomes such as knee function (single leg squats, eccentric step-downs, balance, leg press, and hamstring curls) were recorded at 8 and 12 weeks post-operatively. Significant differences in bone and muscle mass were apparent at 6 and 12 weeks with regard to the whole limb with better results in the restriction group. Better bone mass femur outcomes were apparent in the blood flow restriction group at 12 weeks and lean mass outcomes at both 6 and 12 weeks in the thigh.