Impact of Non-contact Hamstring Muscle Injuries on Match Performance Outcomes in Professional Football Players: A Study Protocol for a Systematic Review and Meta-analysis

T h i s systematic review aims to investigate match physical performance outcomes following hamstring muscle injury in professional football players, with particular attention to changes in global positioning system (GPS) derived external load metrics before and after return to play (RTP).Additionally, the review seeks to explore contextual and injury-related factors that may influence post-injury match performance, such as injury characteristics (e.g., location, severity, time to RTP), and player characteristics.To this end, the proposed systematic review will address the following question: How does match physical performance change after RTP following hamstring muscle injury in professional football players, as measured by GPS-derived metrics, and which contextual factors may influence these outcomes?Rationale Non-contact hamstring muscle injuries are among the most common time-loss injuries in professional football, representing a substantial burden for players and teams due to their high incidence and recurrence rates 1-3.These injuries frequently result in reduced training and match availability and may negatively affect players' ability to meet the physical demands of competition after RTP 3,4.In recent years, the widespread use of GPS and tracking technologies in professional football has