![]() The order from lowest to highest wave intensity at identical submaximal speeds was backstroke, front crawl, breaststroke and butterfly. The four competitive strokes have been shown to produce a different wake, or make waves of different intensity. Furthermore, one study shows an 8% reduction in performance for children performing a 200m swim in waves compared to flat water. the less experienced lifeguards suffered the greatest decrement. They also found a significant effect of experience, i.e. They found a reduction in swimming performance from a pool setting to calm sea swimming of 10-12%, and from calm sea to surf sea swimming of 30-57%. They found significantly slower swimming speed in surf compared to calm sea and in calm sea compared to pool swimming. The differences in lifeguard performance when swimming in a pool versus swimming in the sea in calm and surf conditions were investigated by Tipton et al. There are only a few studies that have investigated swimming performance in outdoor conditions. In Norway only 7% of the drowning cases were in the category “Bathing” – including pool and beach activities, the rest of the accidents in the period of 1998-2010 happened in an outdoor setting (sea, lake, river), i.e. For instance, in the tropical islands of Hawaii, 41% of drowning accidents happened in a pool setting and 39% in a surf or bay area setting. ![]() This order did not change when introducing waves, and the velocity decrement was 4 and 2% for medium and large waves respectively (not significantly different from other strokes).ĭrowning accidents happen in many arenas. ![]() For the subgroup swimming with fins, this was the fastest stroke, followed by front crawl, and head-up crawl. The average velocity decrement when introducing medium and large waves was 3% and 7% respectively. When introducing medium or large waves, the order of strokes from fastest to slowest was identical to flat-water conditions. The fastest stroke in flat water was not surprisingly, front crawl, followed by head-up crawl, back crawl and breaststroke. A repeated measures ANOVA showed a significant effect of stroke, F(3,23)=108 (p<0.001), showing that these four strokes have different levels of performance and wave height F(2,24)=87 (p<0.001), showing that introducing waves reduced velocity, but there was no interaction effect. A subgroup swam front crawl, head-up crawl and head-up crawl with fins. The strokes studied were front crawl, head-up crawl, back crawl and breaststroke. The wave heights were flat, medium (ca 20 cm) or large (ca 40 cm), in a specially designed wave-simulating pool. Thirty-three subjects swam twelve 25m sprints each, in a randomized order, in a 3x4 (wave height x stroke) design.
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