Pre-Season ACL Risk Classification of Professional and Semi-Professional Football Players, via a Proof-of-Concept Test Battery

This study aimed to identify football players at high risk (HR) for anterior cruciate ligament (ACL) injury via a four-test battery and assess possible factors affecting classification. Ninety-one professional and semi-professional male athletes participated in a field-based pre-season screening. The cut-off points of the test battery were 10% acknowledged inter-limb asymmetry limit for quadriceps and hamstring isometric strength and single-leg triple hop for distance, in addition to the upper limit of 6 errors in the landing error scoring system (LESS). Additional assessment of hip adductors and core stability completed the global functional profile of the players. Sixty-one players were identified as HR and thirty as low-risk (LR) for ACL injury. Discriminant analysis showed that the proposed test battery classified accurately 78.0% of them, with 91.8 sensitivity and 61.9% specificity. Only four misclassified players in the LR group were at risk of inadequate treatment. All participants were considered healthy, and history of a previously rehabilitated injury did not interfere with the results. LESS seems to be the best predictor for injury-risk grouping. Prone bridge time was also a whole-body variable discriminating between groups. The proposed test battery provides a promising option for field-based pre-season ACL risk assessment of football players and needs to be studied prospectively.