Effect of a congested match schedule on immune-endocrine responses, technical performance and session-RPE in elite youth soccer players

This study investigated the effects of a congested match schedule (7 matches played in 7days) on steroid hormone concentrations, mucosal immunity, session rating of perceived exertion (S-RPE) and technical performance in 16 elite youth soccer players (14.8 +/- 0.4years; 170.6 +/- 9.4cm; 64.9 +/- 7kg). No change was observed for salivary cortisol concentration across match time points (P=0.33; effect size [ES]=0.13-0.48). In contrast, there was a decrease in salivary testosterone and salivary IgA (SIgA) concentrations from the 1st compared with the last time point (P=0.01 and 0.001, ES=0.42 and 0.67, respectively). The SIgA concentration varied across time points (P<0.001) with the highest value observed at the 3rd time point (rest day) (3rd vs all time point; ES=0.47-0.73). No changes were observed for S-RPE across time points (P>0.05). A higher number of tackles and interceptions were observed during the 4th match vs 1st and 7th matches (P<0.001; ES=2.25 and 1.90, respectively). The present data demonstrate that accumulated fatigue related to participation in a congested match schedule might induce a decrease in testosterone concentration in youth players and negatively affect their mucosal immunity and capacity to perform certain technical actions.