Psycharakis, Stelios and Sanders, Ross (2008) Validity of the use of a fixed point for intracycle velocity calculations in swimming. Journal of Science & Medicine in Sport, 12 (2). pp. 262-265. ISSN 1440-2440

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Abstract/Description

The intracycle velocity (V) of a fixed point on a swimmer’s body, usually the hip, is frequently calculated as a direct indication of the intracycle V of the centre of mass (CM). The purpose of this study was to examine whether the intracycle V of the hip reflects accurately the intracycle V of the CM in freestyle swimming. One stroke cycle was analysed for ten swimmers performing a maximum freestyle swim. The magnitude of differences between CM and hip values was calculated for the instantaneous V values, the intracycle V fluctuation (Vfluc) and the magnitude and timing of appearance of maximum (Vmax) and minimum intracycle V (Vmin). Large differences were found in all variables, with the use of the hip for V calculations overestimating significantly Vmax and underestimating significantly Vmin and Vfluc of the CM (p≤0.001). The results of this study showed that the hip motion should not be used as an indication of the intracycle CM motion in freestyle swimming.

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