Abstract
Unstructured, ad libitum drinking may predispose some athletes to start exercise already slightly hypohydrated (decreased body water). The impact of pre-exercise mild hypohydration on subsequent swimming performance is still unknown. Hence, the goal of this study was to examine its effect on peak force production on the starting block and 100 m front crawl swimming performance in competitive university-level swimmers. At least one hour after having been passively exposed to heat where a body mass loss of 1.5% was induced or euhydration (normal body water) maintained, nine participants (age: 22 ± 2 years) underwent an assessment of their peak force production on the starting block and 100 m front crawl performance. One hour following hypohydration, rectal temperature had returned to baseline in each condition. Urine osmolality and specific gravity were higher (p < 0.05) with hypohydration than euhydration (995 ± 65 vs. 428 ± 345 mOsmol/kg; 1.027 ± 0.003 vs. 1.016 ± 0.007 g/mL) prior to exercise testing, as was perceived thirst. Swimming performance (p = 0.86) and peak force production (p = 0.72) on the starting block did not differ between the hypohydration and euhydrated condition (63.00 ± 4.26 vs. 63.09 ± 4.52 s; 1322 ± 236 vs. 1315 ± 230 N). The current results indicate that mild hypohydration, which may occur with ad libitum drinking, does not impede peak force production on the starting block and 100 m front crawl performance in university-level competitive swimmers. Planned drinking is not required prior to such an event.
Highlights
Swimming has been on the program of the Summer Olympic Games since the first edition of the Games in 1896 [1] and is an extremely popular sport throughout the world
Healthy swimmers (7 men and 2 women) from the University of Sherbrooke swimming team participated in this study, which was approved by the University of Sherbrooke Institutional Review
This study examined the impact of mild hypohydration (1.5% body mass) on 100 m front crawl performance and peak muscle force production on the starting block in university-level competitive swimmers, and to the best of our knowledge, this is the first study to examine the effect of hypohydration on performance within this context
Summary
Swimming has been on the program of the Summer Olympic Games since the first edition of the Games in 1896 [1] and is an extremely popular sport throughout the world. The 100 m front crawl is often considered to represent the blue-ribbon race in competitive swimming. The fourth place finisher missed the first and third place of the podium by only 0.36 and 0.02 s, respectively [2]. This event requires a combination of muscle power and strength to produce a high take-off horizontal velocity at the starting block, which plays a critical role in 100 m swimming performance [3,4], and muscle anaerobic capacity and endurance to maintain a high swimming velocity throughout the distance [5,6,7].
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