Maturity-related developmental inequalities in age-group swimming: The testing of 'Mat-CAPs' for their removal.

OBJECTIVES: To (1) examine the association between maturity timing and performance-based selection levels in (N=708) Australian male 100-m Freestyle swimmers (12-17 years); (2) identify the relationship between maturation status and 100-m Freestyle performance; and (3) determine whether Maturation-based Corrective Adjustment Procedures (Mat-CAPs) could remove maturation-related differences in swimming performance. METHODS: In Part 1, maturity timing category distributions ('Early', 'Early Normative', 'Late Normative' and 'Late') for 'All', 'Top 50%' and '25%' of raw swimming times were examined within and across age-groups. In Part 2, multiple regression analyses quantified the relationship between maturity offset (YPHV) and swimming performance. In Part 3, sample-based maturity timing category distributions were examined based on raw and correctively adjusted swim times for 12-17 year old age-groups. RESULTS: Based on raw swim times, a high prevalence of 'Early-maturing' swimmers, with large effect sizes was identified (e.g., 14 years 'All' - χ2 (3, 151=111.98, p<0.001; 'Early' v 'Late' OR=82.0 95%CI=4.77, 1409.9); while a complete absence of 'Late-maturers' was apparent in the sample (N=708). When maturity categories were re-defined based on sample mean±standard deviation, and when using the expected curvilinear trendline identified in Part 2, Mat-CAPs mitigated maturity timing biases across all age-groups and selection levels, and removed the Freestyle performance advantage afforded by advanced maturity timing and status. CONCLUSIONS: Removing the influence of maturation-related developmental differences could help improve youth swimmer participation experiences and improve the accuracy of identifying genuinely skilled age-group swimmers.

Sink or Swim? A survival analysis of sport dropout in Australian youth swimmers.

OBJECTIVES: To examine long-term participation and dropout rates in Australian youth swimming using survival analyses and to determine whether multiple individual, socio-demographic, and competition-related factors influenced dropout. DESIGN: Retrospective cohort study of registration and competitive performance data. METHODS: Part 1-Registration data from N = 17 161 female (n = 9400) and male (n = 7761) New South Wales (NSW) swimmers aged 10-15 years (inclusive). Part 2-Competition level involvement in a subsample of female (n = 1011) and male (n = 811) swimmers, aged 12-15 years, was also examined. To determine dropout rates and influential factors, Kaplan-Meier survival analyses supplemented by Cox regression were used. RESULTS: (1) Kaplan-Meier analyses identified median sustained participation rates of four years (95% CI = 3.93-4.06), with 15.9% maintaining participation over 10 years. Cox regressions identified age-group was associated with dropout (P < .001), with a 184.9% higher Hazard Rate (HR) for 10- vs 15-year-olds. Residential proximity to major cities was associated with dropout (P < .001), with urban swimmers reporting a 24.8% higher HR rate than rural swimmers. Sex and relative age were not associated with dropout. (2) The subsample median sustained participation was five years (95% CI = 4.79-5.20), with 25.3% maintaining participation for ten years. Level of competition was associated (P < .001), with an 86% higher HR when considering lower competition levels (ie, club/district v national). CONCLUSION: In a large representative sample of swimmers, survival analyses identified age-group, competition level, and city proximity were associated with increased swimming dropout rates.