314 p.The aim of the present study was to determine anthropometric, physical and physiological characteristics of high level players, to analyze how these parameters change across time and to determine their relevance in the selection process of a professional soccer club. The study involves a longitudinal analysis during 4 competitive seasons of young soccer players of the Athletic Club of Bilbao that were evaluated annually on two occasions. Anthropometry, physical performance tests, salivary hormones concentration, chronological age and age at peak height velocity were measured. We observed that as players get older they grew and performed better. However, results indicate that changes in performance were significantly affected by growth and maturation. Thus, the patterns of physical growth and maturation of young players merit more detailed consideration. Besides, it seems clear that a large body size and a small amount of body fat are relevant anthropometric parameters involved in the selection process of high level soccer players. Moreover, we observed that anthropometrical and physical performance characteristics can differentiate between players that are selected from those that are not. Also, results demonstrate that these procedures may eliminate late maturer’s with potential and exclude players born late. Finally, it seems that technical staff of the club selects players with a large body size, advanced maturity, and particularly older chronological age and less body fat.La autora del trabajo recibió una beca predoctoral del Gobierno Vasco (BFI2010-35
