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Although sports scientists have been studied performance in young swimmers in many ways, most of them focused in variables which could be part of talent selection, besides that, in many studies were used measures with greater internal validity than ecological validity. Based on the styles and distances of swimming, the variability of gender, growth and development, the aim of this study was understand how performance works on male swimmers in 100 meters front crawl style. Found not only variables that could be predictive for young swimmers aged 12-14 years-old but also use variables that approaching of training day-by-day being scientifically reliable were some of the main concerns of this study. Summarizing, this work provides to scientists and coaches a new point of view between sports science and training in real situation instead of lab situation. In this way, swimming teachers and trainers may reflect about performance results related to growth, development and trainability.

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