title: The interaction between constituent year and within-1-year effects in elite German youth basketball.
abstract: The current state of research on relative age effects in basketball shows an uneven picture. These mixed results might be caused by the interaction of constituent year and within-year effects. Our aim was to examine constituent and within-1-year effects in elite German youth basketball. The sample (n = 4400) included players competing in the JBBL (Under-16 first division) and the NBBL (Under-19 first division) from 2011/2012 until 2013/2014. A multi-way frequency analysis revealed an interaction of constituent year effects and within-1-year effects for the JBBL, χ2(6, 2590) = 12.76, P < 0.05. NBBL data showed significant constituent year effects, χ2(2, n = 1810) = 25.32, P < 0.01, and within-1-year effects for all three age bands but no interaction. The interaction between constituent year and within-1-year effects in the JBBL showed reduced within-1-year effects with increasing age. Once players enter the system in the JBBL, relatively younger players seem less likely to drop out of the system. Results offer new insight regarding how the regulations of this talent development system may influence athletes' opportunities to enter the system and their likelihood of staying at the highest levels of competition.
authors.affiliation: Institute of Sport Science, University of Oldenburg, Oldenburg, Germany.
authors.forename: C
authors.identifier: http://orcid.org/0000-0001-9696-483X
authors.initials: C
authors.lastname: Steingröver
authors.affiliation: Faculty of Health Sciences, University of Ontario Institute of Technology, Oshawa, Ontario, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Wattie
authors.affiliation: School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Baker
authors.affiliation: Department of Kinesiology, Research Centre for Movement Control and Neuroplasticity, KU Leuven, Belgium.
authors.forename: W F
authors.initials: WF
authors.lastname: Helsen
authors.affiliation: Institute of Sport Science, University of Oldenburg, Oldenburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Schorer
mesh_terms: D000293:Adolescent; D000367:Age Factors; D056352:Athletes; D054874:Athletic Performance; D001490:Basketball; D005858:Germany; D006801:Humans; D008297:Male; D000067009:Youth Sports
keywords: Relative age effects; age-grouping policies; expertise; junior basketball; talent development