Inside the academy: Biological maturation practices in Spanish professional football

Background Biological maturation varies considerably among adolescent athletes and can significantly influence training, talent identification, and injury risk. However, it remains unclear to what extent professional football academies systematically assess and apply this information in practice. Objectives To investigate how professional Spanish football academies monitor biological maturation, what methods they use, and how this information is applied in training and sport-related decision-making, with comparisons between clubs from the top and second divisions. Methods A total of 36 out of 42 professional Spanish football academies participated in an online survey (17 from the top division and 19 from the second division). The questionnaire addressed whether and how biological maturation is assessed, what specific methods are used, and how the results are applied. Descriptive statistics and comparisons by division level were conducted. Results Only 47% of academies reported formally assessing biological maturation, although 64% indicated that they adapt training content based on developmental factors. Academies from the top division were more likely to perform assessments, use validated methods (e.g., maturity offset, Khamis–Roche), and integrate these data into training and player management decisions. Conclusions There is significant variability in how professional Spanish academies monitor and apply biological maturation. Academies from the top division tend to adopt more advanced and structured practices compared to those from the second division. To promote greater consistency and developmental fairness, standardized monitoring protocols and improved coach education are recommended within the professional football academy system in Spain.