RESUMEN
Estimated ages at take-off (TO) and at peak height velocity (PHV) based on two models and maturity status based upon age at PHV and skeletal age (SA) were compared in a longitudinal sample of male soccer players. In addition, estimated ages at PHV in 13 longitudinal samples of soccer players were compared. The longitudinal height records of 58 players of European ancestry, measured annually on four or five occasions between 11 and 16 years, were modeled with Superimposition by Translation and Rotation (SITAR) and Functional Principal Component Analysis (FPCA) to estimate ages at TO and PHV. SAs were assessed with the Fels method. Ages at PHV in 13 longitudinal samples of soccer players (Europe 7, Japan 6) were evaluated with meta-analysis. Estimated ages at TO, 11.2 ± 0.8 (SITAR) and 11.0 ± 0.8 (FCPA) years, and at PHV, 13.6 ± 0.9 (SITAR) and 13.7 ± 0.0 (FCPA) years, were similar. An earlier age at PHV was associated with advanced skeletal maturity status (rho = -0.77 at ~14 years). Ages at PHV among European players indicated a north (later) - south (earlier) gradient, and were later than ages at PHV among Japanese players. In summary, ages at TO and PHV were similar with SITAR and FPCA, and ages at PHV were most strongly correlated with SA at ~14 years. Mean ages at PHV showed a north-south gradient among European samples, and were later compared to Japanese samples.
RESUMEN
Abstract The study examined the presence of the relative age effect (RAE) and association between birth quartile and anthropometry, biological maturation and physical and technical performance of young Brazilian soccer players. The sample included 119 male players, 74 of U-15 category and 45 of U-17 category, which were divided into quartiles according to the birth year. Biological maturation was assessed using the method of skeletal age of Fels. Anthropometric measurements included body weight, stature and subcutaneous adiposity. Physical fitness assessment included strength tests in the lower limbs, speed, aerobic endurance and anaerobic power. Technical skills included ball control, dribbling and kicking accuracy. Overall, 65.5% of soccer players were born on the first half of the year (c2= 8.069, p = 0.04); however, in the analysis by category, there was no significant difference in the distribution of birth dates for quartile when compared with the reference population (U-15: c2=6.322, p=0.10; U-17: c2=2.339, p=0.50). MANCOVA revealed no significant differences between anthropometry, biological maturation and physical and technical performance in both competitive categories. These results suggest that there is a higher proportion of young Brazilian soccer born on the first months of the year, but that RAE does not necessarily constitute an advantage under the anthropometric, physical and technical standpoint. The process of biological maturation of individuals should be considered by coaches in the selection of athletes.
Resumo O estudo teve como propósito investigar a presença do efeito da idade relativa e a influência do quartil de nascimento na antropometria, maturação biológica e desempenho físico e técnico de jovens futebolistas. Foram amostrados 119 futebolistas do sexo masculino, sendo 74 da categoria infantil (sub-15) e 45 da categoria juvenil (sub-17). A data de nascimento dos atletas foi dividida em quatro quartis. Foram avaliadas a massa corporal, a estatura e as dobras cutâneas. A maturação biológica foi acedida através da idade esquelética, pelo método de Fels. O desempenho físico incluiu testes de força de membros inferiores, velocidade, resistência aeróbica e potência anaeróbica. O desempenho técnico foi avaliado pelas provas de controle da bola, condução da bola e precisão de chute. No geral, 65,5% dos futebolistas nasceram no primeiro semestre do ano (c2=8,069, p=0,04), porém, na análise por categoria, não houve diferença significante na distribuição das datas de nascimento por quartil quando comparado com a população de referência (sub-15: c2=6,322, p=0,10; sub-17: c2=2,339, p=0,50). A MANCOVA não revelou diferenças significantes entre os quartis na antropometria, maturação biológica e desempenho físico e técnico em ambas as categorias competitivas. Estes resultados sugerem que existe maior proporção de jovens futebolistas brasileiros nascidos nos primeiros meses do ano, mas que o EIR não constitui necessariamente uma vantagem sob o ponto de vista antropométrico, físico e técnico. Os processos individuais de maturação biológica devem ser considerados pelos técnicos na seleção dos atletas.