Effect of pre-season training phase on anthropometric, hormonal and fitness parameters in young soccer players

The aims of the study were to investigate 1) the effect of 8 weeks of PSP training on anthropometrics, salivary hormones and fitness parameters in youth soccer players, 2) the correlations between fitness and hormonal parameters, and 3) the impact of the experience of the coach and his methodology of training on these parameters. Weight, height, BMI, pubertal development (PDS), salivary Cortisol (sC), salivary Testosterone (sT), salivary sDHEAS, intermittent tests (VO2max), and countermovement jump test (CMJ) modifications of 35 youth soccer players (age: 14 +/- 0 yrs; BMI: 20.8 +/- 1.8 k/m(2)) from two Italian clubs ("Lupa Frascati" -LF-; "Albalonga" -AL) were analysed. A significant (p<0.05) time by club effect was observed in sC (F-(1,F-31) = 9.7, ES = 1.13), sT (F-(1,F-31) = 4.2, ES = 0.74), CMJ (F-(1,F-28) = 26.5, ES = 1.94), and VO2max (F-(1,F-28) = 8.5, ES = 1.10). Statistical differences (p<0.05) in weight (F-(1,F-32) = 25.5, ES = 0.11), sC (F-(1,F-31) = 32.1, ES = 1.43), sT/sC ratio (F-(1,F-31) = 10.1, ES = 0.97), sDHEAS/sC ratio (F-(1,F-31) = 6.3, ES = 0.70), and VO2max (F-(1,F-28) = 64.3, ES = 1.74) were found within time factor. Between clubs, differences (p<0.05) in sC (F-(1,F-32) = 8.5, ES = 1.17), sT (F-(1,F-31) = 4.2, ES = 0.74), CMJ (F-(1,F-28) = 26.5, ES = 1.50), and VO2max (F-(1,F-28) = 8.5, ES = 1.10) were found. CMJ was inversely correlated with sDHEAS (r = -0.38) before PSP, while Delta of CMJ showed significant correlations with Delta of sC (r = 0.43) and Delta VO2max was inversely correlated with Delta BMI (r = -0.54) and Delta sC (r = -0.37) in all subjects. Considering each single club, Delta VO2max showed correlations with Delta BMI (r = -0.45) in AL, while CMJ showed correlations with Delta PDS (r = 0.72) in LF club. Since the PSP is often limited training time to simultaneously develop physical, technical and tactical qualities, an efficient method to distribute the training load is important in youth soccer players to increase the performance and to avoid injuries.