Estimating time-to-contact with temporal occlusion in relay swimming: a pilot study.

The purpose of this study was to analyse swimmers' perceptual judgements of a simulated time-to-contact task in freestyle swimming relays. The study sample consisted of 31 national-level swimmers of both genders (n = 18 males, 17.22 ± 1.95 yrs.; n = 13 females, 14.61 ± .76 yrs.). Participants were asked to watch two videos corresponding to the last course of a given swimmer during a competition of 4 × 100 m and 4 × 200 m freestyle events. These videos were presented with temporal occlusion correspondent to predetermined approaching distances (7.5, 5.0, and 2.5 m). Participants were required to simulate a typical position in standby for exiting the block and estimate the time-to-contact of the incoming swimmer by pressing a switch. A Wilcoxon test was performed to determine differences between time-to-contact and real contact time. The results showed that estimation of time-to-contact was generally lower than real contact time at all approaching distances (with occlusion) and for both genders (p < .05), except at a 7.5-m distance in the men's 4 × 200 m (p = .744; r = .09) and at 5.0 m in both the 4 × 100 m and 4 × 200 m for the female group (p = .279, r = .22 for 4 × 100 m; p = .2453, r = .17 for 4 × 200 m). The larger variation (Δ) between estimation and real contact time was found at a 7.5 m occlusion distance in the female 4 × 100 m (p < .001; r = .82). Swimmers tend to underestimate the time-to-contact of the incoming swimmer, in the context of a simulated relay race. Taken together, these results highlight the importance of perceptual abilities development in swimmers to optimize their technique and effectiveness during relay starts.