XX Genotype Negatively Affects Running Performance and Increases Muscle Injury Incidence in Football Players.

The aim of this study was to investigate the association of the rs1815739 polymorphism with match running performance and injury incidence in top-level professional football players. A total of 315 top-level professional football players from the first division of Spanish football (i.e., ) participated in this prospective and descriptive study. The rs1815739 genotype was identified for each player using genomic DNA samples. During 2021-2022, players' performance was obtained through a validated camera system in all official matches. Additionally, the incidence of non-contact injuries was obtained by each team's medical staff according to the International Olympic Committee (IOC) statement. From the study sample, 116 (36.8%) players had the RR genotype, 156 (49.5%) had the RX genotype, and 43 (13.7%) had the XX genotype. The anthropometric characteristics of the players were similar across genotypes. However, the total running distance ( = 0.046), the distance at 21.0-23.9 km/h ( = 0.042), and the number of sprints ( = 0.042) were associated with the genotype. In all these variables, XX players had lower match performance values than RR players. Additionally, total and match injury incidences were higher in XX players than in RR players ( = 0.026 and 0.009, respectively). The rate of muscle injuries was also higher in XX players ( = 0.016). football players with the XX genotype had lower match running performance and a higher incidence of non-contact injuries over the season.