Two Percent Hypohydration Does Not Impair Self-Selected High-Intensity Intermittent Exercise Performance

Naoyuki Yamashita; Ryo Ito; Masataka Nakano; Takaaki Matsumoto

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Two Percent Hypohydration Does Not Impair Self-Selected High-Intensity Intermittent Exercise Performance

Yamashita, Naoyuki ^[1] ; Ito, Ryo ^[2] ; Nakano, Masataka ^[3] ; Matsumoto, Takaaki ^[1]
1. [1] Chukyo University
  
  Chukyo University
  
  Naka-ku, Japón
2. [2] Nihon Fukushi University
  
  Nihon Fukushi University
  
  Japón
3. [3] Aichi Toho University
  
  Aichi Toho University
  
  Naka-ku, Japón
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Localización: Journal of strength and conditioning research: the research journal of the NSCA, ISSN 1064-8011, Vol. 29, Nº. 1, 2015, págs. 116-125
Idioma: inglés
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Resumen
- The level of hypohydration at which power output during intermittent exercise performance starts to decrease is not fully understood. The purpose of this study was to investigate the effects of 2% hypohydration without hyperthermia on intermittent exercise performance. Eight collegiate amateur boxers completed 2 exercise tests. On day 1, subjects hypohydrated by 2% of body mass by exercising in a hot environment, and on day 2, subjects performed intermittent exercise (4 × 2 minute per round [R] separated by 1-minute recovery) under a randomly assigned condition of with (HYP) or without (EUH) hypohydration. Each bout consisted of 8 × 5 seconds of maximal cycling exercise (0.05 kp × body mass) separated by 10 seconds of passive recovery. Mean power output per kilogram (MPO), total power output per kilogram (TPO), energy system relative contribution, and core rectal temperature (Tre) were measured. Changes in body mass before the exercise tests were -2.25 ± 0.18% (HYP) and -0.17 ± 0.19% (EUH) (p < 0.001). Mean power output, TPO, and each energy contribution ratio were not significantly different between the trials, and pre- and postexercise test Tre did not differ significantly between trials. Results demonstrated that approximately 2% hypohydration lies below the point at which power output during intermittent exercise starts to decline.