Performance Progression of British Swimmers Through Adolescence: A Longitudinal Study

Introduction: Current research suggests that there are differences in the sporting performance of males and females. It has also been noted that the career trajectories of swimmers are affected by gender. Part I of this study used historic rankings data to analyse the trajectories of male and female swimmers to their peak performance. Additionally, it examined the difference in the development of successful junior and successful senior swimmers. The Swimming Discussion Paper was published by British Swimming (2018) to highlight some of the patterns of performance at the Nationalchampionships, which observed a general decline in the performance of females from the national qualification events to the national championships. Part II of the study aimed to confirm and develop the findings of the Swimming Discussion Paper to identify differences in the short-term performance progression of males and females between qualification and National championships. Methods: In part I of the study, male and female swimmers with the top 10 junior and top 10 senior all-time British rankings for each event were included for analysis. In total, 44901 historic performance observations for 269 unique swimmers were obtained from the British Rankings database. Swimmers who were successful in both the junior and senior rankings lists were allocated to the Junior & Elite (JE) group. Mean ages of peak performance were determined for each swimming event for each group of swimmers. A quadratic model was fit to the data and assessed using a multi-variate ANOVA with a significance level of p<0.05. Part II of the study used data from the British Summer Meet (National championships) from 2016-2019. This resulted in 13477 national qualification swims and their associated national championship swims in the same year by 2716 unique swimmers. A multi-variate ANOVA was used to assess the significance of each factor (sex, age group, distance, stroke and year) upon the percentage change in performance time between qualification and nationals. Results: Part I found that more females than males converted their top-ranking junior performance into a top-ranking senior performance. Females were confirmed to achieve their peak performance at a younger age than males (19.7±3.0 and 21.3±3.3 years respectively, p<0.05). When events were grouped by stroke and distance, the largest gap in the mean age of peak performance between males and females in the same event was found in breaststroke (2.9 years) and for the 200m events (2.1 years). Generally, the difference between males and females was least in longer events. Career trajectories of swimmers in different groups were found to be significantly different, as were the trajectories of male and female swimmers. Part II found that breaststroke events showed the least progression between qualification and nationals, particularly for females. Events of 200m in length were found to show the least progression. On average, females show less of a performance progression than males. However, females showed a more consistent pattern of performance change across age groups. Faster, higher ranked male and female swimmers were consistently producing positive performance progressions from qualification to nationals. Conclusion: This study confirmed that there are differences in the progression of male and female swimmers throughout adolescence. A greater proportion of females translated their successful junior performances into a top senior ranking, but good junior performance is not a prerequisite to a successful senior performance. This study corroborated the overall finding of the Swimming Discussion Paper, but revealed that the results are more nuanced than previously reported. To ensure success for the country on an international level, talent development programmes should aim to include as many swimmers as possible at all levels, as junior performances are not always an indicator of senior success.