Lifeguard's swimming: Front-Crawl's and up-head front Crawl's energetics

Abstract

Lifeguards use, as part of aquatic rescue, the front crawl and up-head front crawl. Studies on energy expenditure and complementary physiological variables obtained during aquatic rescue strategies are rare. The aim of this study was to compare the front-crawl's and up-head front crawl's energetics and performance as carried out by lifeguards. Twenty-one military lifeguards voluntarily participated in this study. Two tests were performed at maximum intensity: 100-meters in both front crawl and up-head front crawl. From each test, physiological data (direct measurement of oxygen uptake, lactacidemia, and heart rate), rate of perceived exertion, and mean swimming speed (two-dimensional video-analysis) were identified. Each energetic source contribution and energy cost were calculated. Descriptive and inferential statistics were used for α < .05. The performance was better in the front-crawl, the physiological results were similar between front-crawl and up-head front crawl, and higher energy cost in up-head front crawl (1.90 ± 0.33 kJ.m-1) compared to the frontcrawl (1.51 ± 0.33 kJ.m-1). In conclusion, the up-head front crawl is less economical when compared to the front-crawl.