The relative age effect in a professional football club setting
Deutscher übersetzter Titel: | Der relative Alterseffekt in einem Profi-Fußballverein |
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Autor: | Mujika, Iñigo; Vaeyens, Roel; Matthys, Stijn P.J.; Santisteban, Juanma; Goiriena, Juan; Philippaerts, Renaat |
Erschienen in: | Journal of sports sciences |
Veröffentlicht: | 27 (2009), 11, S. 1153-1158, Lit. |
Format: | Literatur (SPOLIT) |
Publikationstyp: | Zeitschriftenartikel |
Medienart: | Elektronische Ressource (online) Gedruckte Ressource |
Sprache: | Englisch |
ISSN: | 0264-0414, 1466-447X |
DOI: | 10.1080/02640410903220328 |
Schlagworte: | |
Online Zugang: | |
Erfassungsnummer: | PU201409008602 |
Quelle: | BISp |
Abstract
The relative age effect is an uneven distribution of birth date favouring subjects born in the initial months of a selection year. This study compared the birth-date distributions between several subgroups of Basque football players to identify whether the relative age effect is influenced by age and/or skill level. The study comprised 13,519 players including 114 senior professionals from the Spanish league's AC Bilbao over 21 seasons; over the season 2005–2006, it comprised elite youth (n = 189) from the same club's academy; regional youth (n = 4382) U11–U14 locally federated players; school youth (n = 8834) U10–U11 locally registered school district players. Differences between the observed and expected birth-date distributions were tested based on data from the general Basque male population. Significant chi-square values were followed up by calculating odds ratios and 95% confidence intervals (CI) for the quartile and half-year distributions to examine subgroup differences in the relative age effect. Birth-date distributions of all groups of players showed a significant bias towards early birth in the selection year compared with the reference population (senior, χ2 3 = 24.4, P < 0.001; elite youth, χ2 3 = 59.1, P < 0.001; regional youth, χ2 3 = 41.4, P < 0.001; school youth, χ2 3 = 40.9, P < 0.001). Between-group comparison revealed that the relative age effect incidence progressively increased with a higher level of involvement in youth football. This bias represents a significant loss of potential youth football talent. Verf.-Referat