OBJECTIVES: To investigate the effect of multiple seasons of play on serum S100B concentration in male professional rugby players, while also assessing the acute effects following a season of play and concussion. METHODS: A prospective study of professional male rugby players over three seasons (2016/17 to 2018/19) was conducted. Serum sampling was carried out during pre-season, post-season and following a concussion
sustained during match play at a home game (between 2-24hrs), during each season. Serum S100B concentrations were determined by ELISA assay. RESULTS: Fourteen players sustained 24 concussions over three seasons, of which 13 samples (54%) were collected. Pre- and post-season serum S100B remained stable across multiple seasons. S100B concentration increased significantly following concussion compared with pre-season ( CONCLUSION: S100B remains stable across multiple seasons of play in professional rugby players. As concussion results in a temporary increase in S100B concentration, returning to pre-season values by post-season, S100B may be a useful diagnostic marker for improving existing management protocols for sports-related concussions.