Validity of the use of a fixed point for intracycle velocity calculations in swimming

Psycharakis, Stelios G.; Sanders, Ross H.

Abstract

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.

Citation

Psycharakis, S. G., & Sanders, R. H. (2009). Validity of the use of a fixed point for intracycle velocity calculations in swimming. Journal of Science and Medicine in Sport, 12(2), 262-265. https://doi.org/10.1016/j.jsams.2007.11.008

• Journal Article Type: Article
• Publication Date: 2009-03
• Deposit Date: Jan 26, 2009
• Journal: Journal of Science and Medicine in Sport
• Print ISSN: 1440-2440
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 2
• Pages: 262-265
• DOI: https://doi.org/10.1016/j.jsams.2007.11.008
• Keywords: Biomechanics; Three-dimensional; Centre of mass; Hip; Freestyle; Accuracy
• Public URL: http://researchrepository.napier.ac.uk/id/eprint/2472
• Publisher URL: http://dx.doi.org/10.1016/j.jsams.2007.11.008