Variations in age-related performance progression in competitive swimmin

Purposes: Two separate studies were completed. The purpose of the first study (variations in performance progression within a population) was designed to profile the performance progression and dropout rate of the successful preadolescent swimmers in the U.S. and to examine factors contributing to their subsequent success throughout adolescence and into adulthood. The second study (variations in performance progression between populations/regions) was initiated in order to determine 1) the relationship between age-related height growth and swim performance progression for two ethnically and geographically disparate populations (the U.S. and Japan), known to differ in the timing of maturation and 2) the extent to which interpopulation differences (between American and Japanese) in age-related height growth pattern are related to differences in age-related swim performance progression.;Methods: Study 1: The USA Swimming database and NCAA rankings were used to track the top 100 nine-year-old girls and boys in the 45.7-meter (50-yard) freestyle in 2004. The following data were analyzed: 1) annual best swim times and 2) corresponding rankings in all swim events for each of the subsequent nine years and 3) collegiate rankings from 2013 to 2016. In addition, an online survey was sent to the top 100 nine-year-old girl and boy swimmers in order to examine identifiable factors contributing to senior athletic achievements. A mixed-effect logistic regression was used to illustrate the top 100 sustainability and dropout rate in the 200 nine-year-old swimmers (boys plus girls), and to determine factors contributing to the US top 100 attainments in the sport of competitive swimming across adolescence and into adulthood. Study 2: All available 50-meter long course freestyle times of girl and boy swimmers in 2008, in the U.S. (US) and Japan (JPN), were compiled from the USA Swimming and Japanese swimming federations' database, respectively. Growth reference data (median height for adolescent ages) were also acquired for US. (Kuczmarski et al., 2002) and JPN (MEXT, 2000). Cross-correlation analysis was used to demonstrate the relationship between age-related height growth and swim performance progression for US and JPN, and to examine the extent to which interpopulation differences in height growth (US to JPN ratio) are related to those in swim performance progression.;Results: Study 1: An effect of age on the odds that the top nine-year-old swimmers ranked within the top 100 in 45.7Fr across adolescence was revealed for both sexes. Nearly half of the US top 100 nine-year-old swimmers continued to rank within the US top 100 during late adolescence in both sexes, while approximately one third of the early successful swimmers dropped out from competitive swimming (and/or USA Swimming) by age 18 years. Patterns of the performance retention at a successful level throughout adolescence were similar between sexes but not participation retention (dropout rate), especially at late adolescence. Based on the survey responses (19 girls and 21 boys), the early successful preadolescent swimmers were not necessarily early maturers but were, on average, a group of taller children, especially at early adolescence (above the 95 percentile of US growth data). In addition, there were six significant factors identified for the sustainability of the US top 100 status in competitive swimming. Study 2: A significant association between age-related height growth and swim performance was revealed for both sexes in US and JPN. Japanese girls and boys appeared to be early maturers as compared with US peers (approximately a two-year difference in the age at peak height gain), while swimmers in JPN appear to develop their performance (i.e., gaining growth-related advantages in performance improvements) at earlier ages than US counterparts. The interpopulation difference in height growth was significantly associated with swim performance progressions in both sexes.;Conclusions: Study 1: Early success appears to be an important predictor for future success in competitive swimming, and dropout rate of early successful young swimmers during adolescence is lower than the commonly reported rates. Contributing factors for future success would differ based on the characteristics of athletes (e.g., age, sex, and competitive levels) and types of domain sports examined. Therefore, persistent participation may represent a strategic priority on the local as well as the national level. Study 2: Maturation-related superiority in swim performance was observed between populations. Interpopulation variations in the timing of maturational events (as measured by age-related peak height gain) partially explain differences in adolescent athletic performance. Thus, maturity status may also be an interesting consideration in predicting performance outcomes at international competitive events. (Abstract shortened by ProQuest.).