This study, part of the “CUTtheACL” project, analyzes ground reaction forces (GRF) in over 1000 young football players during a 90° change of direction (COD) task. It offers the largest dataset to date for this movement, aiming to support injury prevention—especially ACL injuries—and return-to-sport decisions.

The research examined GRF in three directions (vertical, anterior-posterior, and medial-lateral), focusing on phases of load acceptance and propulsion. Key metrics included peak forces, ground contact time, and rate of force acceptance.

Results showed that male and elite players generated higher and more efficient forces than female and subelite players, indicating better movement control and performance. The study also highlights how specific GRF patterns may reveal poor mechanics or increased injury risk.

Despite being limited to a healthy, young population and a planned COD task, this research provides valuable reference data and practical tools—like GRF curve interpretation—for clinicians to assess athletic movement and guide training or rehabilitation.