Real-Time Biofeedback to Target Risk of Anterior Cruciate Ligament Injury: A Technical Report for Injury Prevention and Rehabilitation

CONTEXT: Biofeedback training enables an athlete to alter biomechanical and physiological function by receiving biomechanical and physiological data concurrent with or immediately after a task. OBJECTIVE: To compare the effects of 2 different modes of real-time biofeedback focused on reducing risk factors related to anterior cruciate ligament injury. DESIGN: Randomized crossover study design. SETTING: Biomechanics laboratory and sports medicine center. PARTICIPANTS: Female high school soccer players (age 14.8 ± 1.0 y, height 162.6 ± 6.8 cm, mass 55.9 ± 7.0 kg; n = 4). INTERVENTION: A battery of kinetic- or kinematic-based real-time biofeedback during repetitive double-leg squats. MAIN OUTCOME MEASURES: Baseline and posttraining drop vertical jumps were collected to determine if either feedback method improved high injury risk landing mechanics. RESULTS: Maximum knee abduction moment and angle during the landing was significantly decreased after kinetic-focused biofeedback (P = .04). The reduced knee abduction moment during the drop vertical jumps after kinematic-focused biofeedback was not different (P = .2). Maximum knee abduction angle was significantly decreased after kinetic biofeedback (P < .01) but only showed a trend toward reduction after kinematic biofeedback (P = .08). CONCLUSIONS: The innovative biofeedback employed in the current study reduced knee abduction load and posture from baseline to posttraining during a drop vertical jump.