Intra- and Inter-Rater Reliability of a Systematic Video Analysis of ACL Injuries in Elite Men's Football

While systematic video analysis is widely used to understand anterior cruciate ligament (ACL) injury mechanisms and contexts, human observation reliability remains a source of concern. This study evaluates the intra- and inter-rater reliability of a systematic video-analysis checklist for assessing ACL injuries in elite men's football. Twenty-five match-related injuries from the top six European leagues (2020-2024) were randomly selected. Independent observers assessed contextual and situational (sunny weather, match minute, playing phase, field location, injury side, dominant leg, and situational pattern), biomechanical (player contact and anatomical area of player contact), and neurocognitive (attentional inhibition and motor response inhibition) variables. Reliability was calculated using Cohen's kappa (κ) and Intraclass Correlation Coefficients (ICC). Quantitative variables and macro-contextual factors, including injury side, playing phase, and situational pattern (0.810 < κ < 1.000) revealed near-perfect to perfect agreement. Biomechanical details exhibited substantial agreement (0.601 < κ < 0.784). Neurocognitive variables only reached moderate to substantial agreement (0.503 < κ < 0.752), while visual speed estimations proved highly unreliable (-0.106 < κ < 0.412). The checklist is a highly reliable tool for evaluating the contextual and situational patterns of ACL injuries, but visual speed estimation should be removed or replaced by objective tracking technologies.