HAND/FOREARM PROPULSION BEST AT 90º TO THE LINE OF PROGRESSION

Silva, A. J., Marinho, D. A., Reis, V. M., Alves, F. B., Vilas-Boas, J. P., Machado, L., & Rouboa, A. I. (2008). Study of the propulsive potential of the hand and forearm in swimming. ** ACSM 55th Annual Meeting Indianapolis, ** Presentation Number, 1436.

This study analyzed the propulsive forces in a swimmer hand/forearm using computational fluid dynamics. A 3-D domain was created to simulate the fluid flow around a model of a swimmer's hand and forearm. Models were created by computerized tomography scans of a male swimmer. Steady-state computational fluid dynamics analyses were performed. Flow velocities were chosen to be within or near the range of typical hand velocities during the swimming underwater path: from 0.5 m/s to 4.0 m/s. Angles of attack of the hand/forearm models of 0º, 45º and 90º, with sweepback angles of 0º, 90º, 180º and 270º were used for the calculations. The combined hand and forearm forces were divided into drag and lift coefficients.

The coefficient of drag was markedly higher than the coefficient of lift at all angles of attack and sweepback. The coefficient of lift, although minor, was highest at an angle of attack of 45º and a sweepback angle of 180º. The coefficient of drag was notably highest at an angle of attack of 90º.

**Implication**. The lower arm/hand propulsive surface is most effective when at 90º to the line of intended propulsion.

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