Growth influences biomechanical profile of young talented swimmers after the summer break
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2014-09-15
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O presente estudo teve como objetivo analisar o efeito do crescimento na biomecânica/técnica de jovens nadadores após as férias de verão. Vinte e cinco nadadores portugueses (12.45 ± 0.94 anos de idade), foram sujeitos a vários testes antropométricos e biomecânicos no final da época 2011-2012 (pré-teste) e 10 semanas mais tarde no início da época 2012-2013 (pós-teste). Foram obtidos a estatura, a envergadura, a área palmar e a área plantar como indicadores antropométricos, e a distância de ciclo, a frequência gestual, o índice de nado, a eficiência propulsiva, o arrasto ativo e o coeficiente de arrasto como variáveis biomecânicas. A velocidade média obtida num esforço máximo de 25 m crol foi tida como o indicador de performance. Após as 10 semanas os nadadores apresentaram-se mais altos, com uma maior envergadura e áreas palmar e plantar. Foram ainda determinadas melhorias significativas na distância de ciclo, índice de nado, eficiência propulsiva e performance. Contrariamente a frequência gestual, o arrasto ativo e o coeficiente de arrasto ativo permaneceram inalterados. Quando controlando o efeito do crescimento nenhuma das variáveis biomecânicas apresentou variações significativas. A performance apresentou associações significativas com as variáveis biomecânicas e antropométricas no pré-teste e no pós-teste, respetivamente. Os resultados demonstram que, apesar de 10 semanas de destreino, os nadadores desta faixa etária conseguem mesmo assim evidenciar melhorias na técnica/biomecânica que são explicadas pelo processo de crescimento e desenvolvimento.
This study aimed to analyze the effect of growth on to biomechanical profile of talented swimmers after the summer break. Twenty-five young swimmers (12.45 ± 0.94 years of age) undertook several anthropometric and biomechanical tests at the end of the 2011-2012 season (pre-test) and 10 weeks later at beginning of the 2012-2013 season (post-test). Height, arm span, hand surface area and foot surface area were collected as anthropometric features, while stroke frequency, stroke length, stroke index, propelling efficiency, active drag and active drag coefficient as biomechanical variables. The mean swimming velocity during an all-out 25 m front crawl effort was used as the performance outcome. After the 10 week break the swimmers were taller with an increased arm span, hand and foot areas. Increases in stroke length, stroke index, propelling efficiency and performance were also observed. Conversely, the stroke frequency, active drag and drag coefficient remained unchanged. When controlling the effect of growth no significant variation was determined on the biomechanical variables. The performance presented high associations with biomechanical and anthropometric parameters at pre-test and post-test, respectively. The results show that young talented swimmers still present biomechanical improvements after a 10 week break, which are mainly explained by their normal growth.
This study aimed to analyze the effect of growth on to biomechanical profile of talented swimmers after the summer break. Twenty-five young swimmers (12.45 ± 0.94 years of age) undertook several anthropometric and biomechanical tests at the end of the 2011-2012 season (pre-test) and 10 weeks later at beginning of the 2012-2013 season (post-test). Height, arm span, hand surface area and foot surface area were collected as anthropometric features, while stroke frequency, stroke length, stroke index, propelling efficiency, active drag and active drag coefficient as biomechanical variables. The mean swimming velocity during an all-out 25 m front crawl effort was used as the performance outcome. After the 10 week break the swimmers were taller with an increased arm span, hand and foot areas. Increases in stroke length, stroke index, propelling efficiency and performance were also observed. Conversely, the stroke frequency, active drag and drag coefficient remained unchanged. When controlling the effect of growth no significant variation was determined on the biomechanical variables. The performance presented high associations with biomechanical and anthropometric parameters at pre-test and post-test, respectively. The results show that young talented swimmers still present biomechanical improvements after a 10 week break, which are mainly explained by their normal growth.
Descrição
Dissertação de Mestrado em Ciências do Desporto, Especialização em Avaliação e Prescrição na Actividade Física
Palavras-chave
Nadadores , Jovens , Cinemática , Antropometria