The trade-off between jump performance and ACL injury risk during landings

This preliminary study investigated the effect of different landing techniques during single-leg drop jumps on knee kinematics of both first and second landing, and jump performance, in order to investigate the conflict between anterior cruciate ligament (ACL) injury prevention and performance. Participants were asked to execute maximal single-leg drop jumps with the dominant lower limb, in natural (unrestricted) condition, or as fast as possible, or focusing on soft landing execution. The results revealed that the subjects significantly reduced the knee flexion in the first landing of the fast condition with respect to natural and soft conditions, which could be related to higher risk of ACL injury. The highest knee flexion was recorded in the soft condition, as a strategy to better cushion the movement. No significant differences were found in the frontal plane kinematics. Although the soft landing resulted beneficial for ACL protection during landing, in this condition, subjects exhibited a lower jump height and longer contact time, resulting in an overall poorer performance. These findings highlighted the existence of a conflict between performance and injury prevention, underscoring the importance of balanced approaches to maximize athletic performance and reduce the risk of injuries.