Female relative age effects and the second-quartile phenomenon in young female ice hockey players

Objectives: Relative age effects exist across sports and cultures (Cobley, Baker, Wattie, & McKenna, 2009), though a recent, unusual trend is females born in the second quartile of the selection year are most over-represented on elite teams. The first purpose of this study was to test the hypothesis that the second quartile phenomenon was the result of first-quartile female athletes registering to play male sport. Due to the nature of the collected data, a secondary purpose was to examine relative age effects across female age divisions. Design: Cross-sectional, with multiple chi-square analyses. Method: Players included 29,924 female ice hockey players (ages 7-17 years) from the Ontario Hockey Federation. Birthdates were converted into quartiles following the Hockey Canada selection year. Results: Relative age effects (with the second quartile most over-represented) existed for the entire sample (chi(2) [3, 29923] = 401.95, p < 0.001), those registered for female ice hockey (chi(2) [3, 24984] = 369.90, p < 0.001) and those registered for male ice hockey (chi(2) [3, 4938] = 37.88, p < 0.001). The strength of the effect lessened as athletes aged. Conclusion: It appears the second-quartile phenomenon cannot be explained by athletes' choice to play male sport. Further, female relative age effects appear strongest at younger ages. The discussion includes integration of results with previous literature, along with plausible explanations. (C) 2017 Elsevier Ltd. All rights reserved.