Modeling Workload Evolution throughout a Professional Soccer Season: Variations Based on Players’ Match Participation Profile

Introduction: This study analyzed the evolution of workload-related variables over a full season using quadratic regression and examined differences based on players’ participation profiles. Methods: Thirty-six professional Brazilian soccer players participated, with a total of 260 training sessions recorded. Players were categorized into three groups according to their match participation (i.e., starters, substitutes, and fringe players). External load variables were collected using Global Positioning System devices and included total distance, distance covered at speeds between 19 and 25 km·h -1 , distance covered at speeds exceeding 25 km·h -1 , player load, total accelerations, and decelerations. Internal load was assessed via perceived subjective exertion and mental load variables through cognitive, affective, emotional, motivational load, and mental fatigue. Results: The analysis revealed significant linear and quadratic effects, indicating a U-shape trajectory on perceived subjective exertion and mental fatigue values, while external load showed an inverted U-shape across the season. Starter players exhibited significantly higher values compared with substitute and fringe players. Significant interactions were found, suggesting that the temporal trajectories were different across groups. Conclusion: Workload evolution was influenced by players’ match participation, highlighting the importance of creating player groups beyond simply starters and substitutes for a more comprehensive monitoring of training load.