The main aims of this thesis were to describe the epidemiology of adolescent footballers, to describe how growth and maturation are associated with injury risk in academy male players and to study the accuracy of methods to estimate somatic maturity status.

Injuries occurring during youth can negatively affect academy progression1 and result in long-term health consequences.2 Growth and maturation represent two potential non-modifiable intrinsic risk factors that are unique to adolescent footballers. The literature published on this topic is, however, contradictory and findings in earlier studies are inconsistent.3

This thesis analysed injury, anthropometric and skeletal age data from routine monitoring of players at Athletic Club, whose professional male team plays in Spanish La Liga (1997–2022). Injury classification was based on the consensus of the International Federation of Association Football4 and practitioner’s experience. Individual exposure was recorded since the season of 2011–2012, which allowed us to describe injury incidence …