Intra-Individual Head Depth Variability During the Competitive Swim Start

Abstract

The research on the competitive swim start primarily consists of group mean and maximum depths with little attention given to individual variability. The purpose of this study was to quantify intra-individual racing start depth variability and use it to assess minimum water depth standards. Twenty-two competitive swimmers executed five racing starts into a water depth of 3.66 m. Intra-individual variability was quantified by taking the standard deviation of the maximum depth of the center of the head for the five racing starts executed by each swimmer. The mean value was 0.09 m with a standard deviation of 0.06 m. Analysis of means and standard deviations showed that about one-third of swimmers would be expected to have a head depth deeper than the current minimum water depth requirement (i.e., 1.22 m) for at least 10% of starts. Based on this research conducted in deep water, it seems that swimmers should demonstrate both consistency and control of racing start depth before being permitted to execute starts in shallow water.