De Jesus, Karla, de Jesus, Kelly, Figueiredo, P. A., Goncalves, P., Pereira, S. M., Vilas-Bolas, J. P., & Fernandes, R. J. (2012). Analysis of upper limb dynamometry in two variants of backstroke start technique. Presentation 1914 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

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This study compared the upper limbs' horizontal impulse during backstroke starts performed with the feet parallel and entirely submerged and with the feet parallel and entirely above the water surface in high-level swimmers (N =5). Ss performed two sets of four maximal repetitions of each backstroke start over a distance of 15 m. An iron handgrip instrumented with a load cell recording at 100Hz, was fixed to the starting block and was connected to a Globus Ergometer data acquisition system. The handgrip system was adapted to comply with the swimming rules: 0.30 to 0.60 m above the water both horizontally and vertically. Data were normalized for body weight. The backstroke start variants were divided into three phases: initial starting position, trunk lifting, and release of the hands. The reference instants determined to assess the three phases were characterized in each individual force-time curve.

Similar values were observed for the horizontal impulse between backstroke starts performed with the feet parallel and immersed and the feet parallel and above the water level at the initial starting position phase, at trunk lifting phase, and at release of the hands phase.

Implication. Despite the task constraint provided for the new rules for the backstroke start, high level swimmers applied similar horizontal impulses throughout hands-off phases in both starting variants.

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