HAMSTRING INJURIES IN FOOTBALL: A COMPLEX SYSTEMS APPROACH THROUGH VIDEO ANALYSIS

Hamstring injuries remain the most frequent muscle injuries in football and continue to impose a substantial burden on player availability, performance, and club management. Despite the large body of literature on hamstring injury risk factors, recurrence, and rehabilitation, their incidence is still rising, suggesting that reductionist models do not fully capture the complexity of their etiology. This PhD thesis aimed to investigate hamstring injuries in football through a complex systems approach, using video analysis to integrate biomechanical, contextual, and perceptual-cognitive dimensions of the injury-inciting event. In doing so, the thesis contributes to the second step of the “sequence of prevention” by providing ecologically valid information on how injuries emerge within the dynamic and interactive environment of football. The thesis is structured around a series of complementary studies. First, a systematic 2D video analysis of hamstring injuries in women’s football addressed the limited sex-specific evidence and showed that injuries do not occur exclusively during maximal sprinting, but also during football-specific actions such as passing, lunging, dueling, and ball-related movements. Second, a case report using Model-Based Image Matching reconstructed, for the first time in football, the full-body 3D kinematics of run-type and stretch-type hamstring injuries from uncalibrated broadcast footage, highlighting that different movement solutions may lead to a similar injury outcome. Third, a systematic review synthesized the methodological approaches used in video analysis studies of hamstring injuries in football and led to the development of a comprehensive methodological framework to guide future research and improve data quality, reproducibility, and integration with complementary sources such as MRI, GPS, and clinical information. The thesis also outlines a field-based markerless motion capture perspective for the analysis of stretch-type mechanisms in football-specific tasks. Overall, this work supports video analysis as an ecological and multidimensional tool for understanding hamstring injury mechanisms in football. By bridging biomechanics, neurocognition, and environmental interaction, the thesis advances a more dynamic and sport-specific understanding of injury and provides a methodological foundation for future prevention and rehabilitation strategies.