Biomechanical analysis of selected risk factors for an anterior cruciate ligament (ACL) rupture during training with the ExerCube

Aim: To investigate the biomechanics of lower extremities duringtraining with the ExerCube and identify movements withpotential risk for ACL injury. Background: Exergaming, which combines physical training with cognitivechallenges, is known to be motivating during rehabilitation; however, the external focus of attention and cognitive load of agame may decrease the ability to control knee joint performance,which can be a risk factor for ACL rupture. Methods: The biomechanics during ExerCube training was measured usinga sensor-based motion capture system (Xsens) in seven healthy, female athletes. Two risk factors (10°- 30°knee flexion, knee adduction) were identified during jumps, squats, and lunges. Forstatistical analysis, a two-way within subject linear mixed modelwas used. Results: Healthy female athletes presented both risk factors (10°-30°kneeflexion, knee adduction) in all movements, although to a differentextent. While no significant differences were found for the knee flexion angle, the mean knee adduction angle was significantly higher in lunges (20.53°) compared to jumps (11.99°, p = 0.04).The fraction of movement duration during which the knee flexion angle was between 10°and 30°was 9.04% in lunges, 23.68% insquats, and 34.61% in jumps. Conclusion: Lunges, squats, and jumps are movements with risk for ACLinjury in the ExerCube environment.Further research in a larger sample and with a focus oncombinations of risk factors is needed to evaluate how ExerCube training is best applicable in ACL rehabilitation