Biomechanics of noncontact and indirect contact injuries in èlite male football (soccer) players

Anterior Cruciate Ligament (ACL) injuries remain a significant concern in professional male soccer, affecting players' careers and long-term health. This study investigates the biomechanical differences between noncontact and indirect contact ACL injuries in èlite male soccer players, using the Model-Based Image-Matching technique for detailed three-dimensional reconstruction. Data from 27 cases from top European Leagues, Major League Soccer and major national team competitions were analyzed, revealing distinct patterns in injured limb kinematics between the two mechanisms. Noncontact injuries biomechanics aligned with literature findings, but with a greater knee flexion at the initial contact with the ground. The indirect contact mechanism differed from the noncontact mechanism, exhibiting greater hip adduction, knee internal rotation, and ankle dorsiflexion at the initial ground contact, resulting from the player’s adaptation to a sudden mechanical perturbation. This study emphasizes the importance of considering the specificities of injury mechanisms in designing tailored preventive strategies and highlights the complexity of ACL injury biomechanics in professional male football.