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Advisor(s)
Abstract(s)
O objectivo do presente estudo foi verificar o arrasto hidrodinâmico (D) provocado pela válvula
Aquatrainer®, utilizada na determinação do consumo de oxigénio (VO2) do nadador, no nado da
técnica de crol. A amostra foi constituida por 33 sujeitos, 18 do sexo masculino e 15 do sexo
feminino, sendo que 21 são de nível nacional e 12 de nível regional. Numa distancia de 13m, à
intensidade máxima de nado, foi determinada a velocidade de deslocamento (v), o arrasto activo
(Da), o coeficiente de arrasto (CD) e a potência de nado (Pot), segundo o método da perturbação
da velocidade, com a ajuda de um corpo hidrodinâmico adicional (Kolmogorov e Duplischeva,
1992; Kolmogorov et al, 1997).
Como principais resultados verificamos que apesar de se verificar a tendencia para o aumento do
D com a utilização da válvula, do ponto de vista estatistico tal alteração não é relevante (Total:
p=0.24; Rapazes: p=0,24; Raparigas: p=0,77). Por sua vez, tanto a velocidade máxima de
deslocamento (vmáx) como o CD parecem ser fortemente condicionados pela utilização do
aparelho (pL0,05).
Concluimos que o D extra, provocado pela válvula poderá não ser o único responsável pela
diminuição da vmáx. Factores de ordem técnica poderão ter desempenhado aqui um papel
importante.
The purpose of this study was to determine the drag caused by the Aquatrainer® snorkel, used in the determination of the swimmers oxygen consumption (VO2), in front crawl swimming. The sample consisted of 33 subjects, 18 males and 15 females, of which 21 are from national level and 12 from regional level. In a 13m distance, at maximum swimming intensity, speed, active drag, drag coefficient and power were determined, according to the velocity perturbation method, with the help of an additional hydrodynamic body (Kolmogorov e Duplischeva, 1992; Kolmogorov et al, 1997). Has main results we found that, although it exists a tendency for the hydrodynamic drag (D) to increase with the use of the mask, from a statistical point of view such a change is not relevant (Total: p=0,24; Boys: p=0,24; Girls: p=0,77). In turn, the maximum velocity of displacement (vmax) and CD appear to be strongly conditioned by the use of the apparatus (p≤0,05). We concluded that the extra D, caused by the use of the snorkel, may not be solely responsible for the decrease in vmax. Technical factors may have played an important role in this decrease.
The purpose of this study was to determine the drag caused by the Aquatrainer® snorkel, used in the determination of the swimmers oxygen consumption (VO2), in front crawl swimming. The sample consisted of 33 subjects, 18 males and 15 females, of which 21 are from national level and 12 from regional level. In a 13m distance, at maximum swimming intensity, speed, active drag, drag coefficient and power were determined, according to the velocity perturbation method, with the help of an additional hydrodynamic body (Kolmogorov e Duplischeva, 1992; Kolmogorov et al, 1997). Has main results we found that, although it exists a tendency for the hydrodynamic drag (D) to increase with the use of the mask, from a statistical point of view such a change is not relevant (Total: p=0,24; Boys: p=0,24; Girls: p=0,77). In turn, the maximum velocity of displacement (vmax) and CD appear to be strongly conditioned by the use of the apparatus (p≤0,05). We concluded that the extra D, caused by the use of the snorkel, may not be solely responsible for the decrease in vmax. Technical factors may have played an important role in this decrease.
Description
Keywords
Natação - Crol - Arrasto hidrodinâmico Natação - Crol - Válvula respiratória Natação - Crol - Válvula aquatrainer