Author(s): LUKAVSKÝ, J., KALATA, M., WILIAMS, C., KONARSKI, J., COELHO-E-SILVA, M., ZAHÁLKA, F., FORD, K., MALINA, R., MALÝ, T. , Institution: FACULTY OF PHYSICAL EDUCATION AND SPORT, CHARLES UNIVERSITY, Country: CZECH REPUBLIC, Abstract-ID: 2764

INTRODUCTION:
Change of direction (COD) ability is an important determinant of soccer performance, and the 505 test is a widely used and reliable field-based assessment of COD performance (1). Biological maturation substantially influences neuromuscular performance during adolescence, meaning that performance differences among youth players of the same chronological age (2). Available reference data are predominantly based on chronological age.
METHODS:
Performance on the 505 test of change of direction speed (CODS) in a longitudinal sample of youth soccer players was evaluated. The sample included a cohort of 118 male academy players (465 observations) for whom adult height (PAH) was predicted using the Khamis-Roche method. Percentage of PAH at the time of observation was used as the indicator of somatic maturation. %PAH ranged from 78.8 to 99.1% and spanned the interval of the adolescent growth spurt.
RESULTS:
Results of analyses based on Generalized Additive Mixed Models (GAMM) indicated a nonlinear association between maturity status and CODS performance (edf = 1.81, F = 149.6, p < 0.001; adjusted R2 = 0.59). The fastest improvements in performance occurred among players classified as Pre-PHV and at take-off of the growth spurt, followed by a progressive but non-detrimental deceleration through the interval of the growth spurt. The GAMLSS-LMS modelling showed an excellent fit (GAIC3 = -913.8) and produced maturity-specific centiles (3rd to 97th) for the 505 test.
CONCLUSION:
Overall, the development of CODS was clearly nonlinear and dependent on biological maturation. The results provide a biologically sensitive normative framework that may enhance player monitoring, talent identification and long-term athlete development in soccer academy environments.