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Purpose: To examine the longitudinal relationships between shoulder internal and external rotation (IR and ER) strength, maturity status, and swim performance (aim 1). To determine whether maturity status mediated (partially/fully) the relationship between shoulder IR/ER strength and performance in age-group swimmers (aim 2). Methods: Using a repeated-measures design, anthropometrics, maturity status, shoulder IR/ER strength, and 200-m front-crawl velocity were assessed over 3 competition seasons in N = 82 Australian male competitive swimmers (10–15 y). For aim 1, linear mixed models examined longitudinal relationships between assessed variables. For aim 2, causal mediation analyses examined proportional (in)direct contributions of maturity status between shoulder IR strength and swim performance. Results: For aim 1, linear mixed models identified a significant relationship between shoulder IR strength and swim performance over time (F1,341.25 = 16.66, P R2 = .13, conditional R2 = .91). However, maturity status was influential (ΔAkaike information criterion = −75.8, χ2 = 19.98, P F1,214.1 = 0.02, P = .88). For aim 2, mediation analyses identified maturity status as fully mediating the shoulder IR strength–swim velocity relationship (92.30%, P Conclusions: Shoulder IR and ER strength did not account for variance in longitudinal age-group swim performance independent of maturity status. Interindividual differences in maturity status fully explained the relationship between shoulder IR/ER strength and swim performance. For practitioners, findings promote the need to account for maturation status and question the rationale for upper-limb strength assessment during maturational years.

Purpose: The study aimed to (1) accurately examine longitudinal relationships between maturity status and both technical skill indices and performance in Australian male (N = 64) age-group Front-crawl swimmers (10–15 y) and (2) determine whether individual differences in maturation influenced relationships between technical skill level and swimming performance. Methods: A repeated-measures design was used to assess maturity status and performance on 200-m Front-crawl trial across 2 competition seasons (2018–2020). Assessments were made on 3 to 5 occasions (median = 3) separated by approximately 4 months. Average horizontal velocity and stroke frequency were used to calculate technical skill indices, specifically stroke index, and arm propelling efficiency. Relationships between variables were assessed using linear mixed models, identifying fixed, and random effect estimates. Results: Curvilinear trends best described significant longitudinal relationships between maturity status with horizontal velocity (F = 10.33 [1, 233.77]; P = .002) and stroke index (F = 5.55 [1, 217.9]; P = .02) during 200-m Front-crawl trials. Maturity status was not significantly related to arm propelling efficiency (P = .08). However, arm propelling efficiency was an independent predictor of Front-crawl velocity (F = 55.89 [1, 210.45]; P Conclusions: Maturity status predicted assessment of swimmer technical skill (stroke index) and swimming performance. However, technical skill accessed via arm propelling efficiency was independent of maturation and was predictive of performance. Maturity status influences performance evaluation based on technical skill and velocity. Findings highlight the need to account for maturation and technical skill in age-group swimmers to better inform swimmer evaluation.

To determine whether average growth tempo influenced longitudinal relationships between maturity status and coordination capability using a 15-s hopping task (Aim 1). To investigate how differences in absolute growth tempo were associated with change in coordination capability within and across peak growth (Aim 2).Participants were NFor Aim 1, log-linear mixed model trends identified maturity status and growth tempo were significantly associated with KWithin maturational progression, short-term accelerations in growth tempo corresponded with short-term decreases in K

Objectives (1) Generate accurate estimates of the relationship between decimal age (i.e., chronological and relative) with swimming performance based on longitudinal data. (2) Determine whether corrective adjustment procedures can remove Relative Age Effects (RAEs) from junior/youth swimming. Design Longitudinal and repeated years of cross-sectional performance data were examined. Methods (1) Participants were 553 male 100 m Freestyle swimmers (10–18 years) who participated in ≥five annual events between 1999–2017. Growth curve modelling quantified the relationship between age and swimming performance, permitting corrective adjustment calculations. (2) Participants were N = 2141 male 100 m Freestyle swimmers (13–16 years) who swam at state/national events in 2015–2017. Relative age distributions for ‘All’, ‘Top 50%’, ‘25%’ and ‘10%’ of swimming times were examined based on raw and correctively adjusted swim times. Chi-square, Cramer’s V and Odds Ratios (OR) determined whether relative age (quartile) inequalities existed according to age-groups, selection level and correctively adjusted swim times. Results Based on raw swim times, for ‘All’ swimmers RAEs was evident at 13 and 14 years-old and dissipated thereafter. But, RAE effect sizes substantially increased with selection level, with large-medium effects between 13–15 years-old (e.g., 15 years — Top 50% Q1 v Q4 OR = 2.28; Top 10% = 6.02). However, when correctively adjusted swim times were examined, RAEs were predominantly absent across age-group and selection levels. Conclusions With accurate longitudinal reference data, corrective adjustment procedures effectively removed RAEs from 100 m Freestyle swimming performance, suggesting the potential to improve swimming participation experience and performance evaluation.

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 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.

The purpose of this study was (1) accurately estimate longitudinal relationships between decimal age (i.e., chronological and relative) and performance in Australian female 100 m (N = 765) and 200 m (N = 428) Breaststroke swimmers (10-18 years); and (2) determine whether corrective adjustment procedures could remove Relative Age Effects (RAEs) in an independent sample of age-matched 100 m (N = 2,491) and 200 m (N = 1,698) state/national level Breaststroke swimmers. In Part 1, growth curve modelling quantified longitudinal relationships between decimal age and swimming performance. In Part 2, relative age distributions (Quartile 1-4) for "All", "Top 25%" and "10%" of swimming times were examined based on raw and correctively adjusted swim times for age-groups. Based on raw swim times, finding identified RAE effect sizes increased in magnitude (small-medium) with selection level ("All"-"Top 25%") in 12-14 years age-groups for both events. However, when correctively adjusted swim performances were examined, RAEs were primarily absent across all age-groups and selection levels. Using longitudinal reference data, corrective adjustment procedures removed relative age advantages in female youth Breaststroke performance. Removing the influence of relative age-related differences is predicted to improve the accuracy of identifying genuinely skilled youth swimmers.

Objectives To determine the prevalence, magnitude and transient patterning of Relative Age Effects (RAEs) according to sex and stroke event across all age-groups at the Australian National age swimming Championships. Design Repeated years of cross-sectional participation data were examined. Methods Participants were 6014 unique male (3185) and female (2829) swimmers (aged 12–18 years) who participated in Freestyle (50, 400 m) and/or Breaststroke (100, 200 m) at the National age swimming Championships between 2000–2014 (inclusive). RAE prevalence, magnitude and transience were determined using Chi-square tests and Cramer’s V estimates for effect size. Odds Ratios (OR) and 95% Confidence Intervals (CI) examined relative age quartile discrepancies. These steps were applied across age-groups and according to sex and each stroke event. Results Consistent RAEs with large-medium effect sizes were evident for males at 12–15 years of age respectively, and with large-medium effects for females at 12–14 respectively across all four swimming strokes. RAE magnitude then consistently reduced with age across strokes (e.g., Q1 vs. Q4 OR range 16 year old males = 0.94–1.20; females = 0.68–1.41). With few exceptions, by 15–16 years RAEs had typically dissipated; and by 17–18 years, descriptive and significant inverse RAEs emerged, reflecting overrepresentation of relatively younger swimmers. Conclusions Performance advantages associated with relative age (and thereby likely growth and maturation) are transient. Greater consideration of transient performance and participation in athlete development systems is necessary. This may include revising the emphasis of sport programmes according to developmental stages and delaying forms of athlete selection to improve validity.