The association between GPS-derived external workload metrics and soleus muscle injuries in professional football (soccer) players.

PURPOSE: To investigate the association between external GPS workload metrics and soleus muscle injuries (SMI) in elite professional football. METHODS: A retrospective cohort study was conducted across seven consecutive seasons (2017/2018-2023/2024) in a single Italian Serie A first-team squad. One hundred and sixty player-season observations were included (25.4 ± 3.2 years; goalkeepers excluded), with 4704 match-hours and 31,686 training-hours recorded. SMIs were defined as time-loss soleus muscle complaints (excluding contact injuries) diagnosed by the club medical staff in accordance with FIFA consensus definitions and classified as structural or non-structural. External loads were quantified using 50 Hz GPS (Stats Perform) and included total distance, high-intensity distance (≥16 km·h-1), sprint distance (≥25 km·h-1), and acceleration/deceleration distances (≥±2.0 m·s-2). For injured players, workloads were averaged across the 7- and 28-day window preceding injury (excluding injury day) and compared to control periods of equal duration. Between-player comparisons contrasted injured players' injury periods with control periods in non-injured players. RESULTS: Twenty-nine SMIs (52% were nonstructural) occurred in 17 players. Injured players were older than noninjured players (29.2 ± 3.9 vs. 25.0 ± 3.2 years; p = 0.041). Most injuries occurred in training (83%); incidence was 0.76/1000 training-hours and 1.06/1000 match-hours; injury burden was 10.86 days/1000 hours. No within-player differences were observed between injury and control weeks for any workload metric (p > 0.05). Over 28 days, injured players demonstrated lower sprint distance versus their control month (-37%; p = 0.014; d = -0.71). For between-player analyses, deceleration distance was higher in the 7-day injury period versus noninjured controls (+17%; p = 0.041; d = 0.44), with no 28-day differences. CONCLUSION: SMIs imposed a substantial burden in elite football and were not preceded by acute workload spikes relative to players' own control periods. Findings suggest SMIs may occur within a context of sustained high training volumes, with modest elevations in short-term deceleration exposure and reduced longer-term sprint distance observed prior to injury. LEVEL OF EVIDENCE: Level III.