A. L. Calabro, S. M. Carlson, R. J. Charlton, T. J. Guinn, and W. M. Silvers

Whitworth University, Spokane, WA

Exercise at altitude under hypoxic conditions is known to decrease maximal aerobic power and shift ATP production toward anaerobic energy systems. Creatine monohydrate (CrM) supplementation is known to increase anaerobic power. Many studies have been done on both subjects. However, there is inadequate research on CrM supplementation and its effect on hypoxic performance. PURPOSE: To determine the effect CrM supplementation on peak power (PP), mean power (MP), fatigue index (FI %), heart rate (HR), and oxygen uptake (VO2) during acute hypoxic exercise performance. METHODS: Fourteen healthy, college-aged athletes consisting of 10 males and 4 females completed 2 separate 30-s Wingate (WIN) tests in normoxic (NORM) and acute hypoxic (HYP) conditions without CrM supplementation. For the acute hypoxic condition, participants inspired a 13.7% O2 air mixture for 5-min before, then during the WIN test. At least 24 hrs. separated the normoxic and acute hypoxic WIN tests and the order of air conditions was randomly assigned. Thereafter, all participants completed a 7-day loading phase of CrM (20-g per day taken in 4, 5-g doses at least 3-hrs apart). Following the loading phase, each participant completed another WIN test in acute hypoxia (HYP/C). RESULTS: A repeated measures ANOVA was used to evaluate differences between each condition for each dependent variable. Alpha was p < 0.05 for each ANOVA. There was a significant difference in PP (p=0.036), MP (p=0.005) and VO2 (p=0.046), and no significant difference in HR (p=0.385) and FI% (p= 0.555) between all conditions. Pairwise comparisons indicated significant increases in PP (p=0.009) and MP (p=0.013) for HYP/C compared to HYP. In addition, VO2 was significantly lower during NORM compared to HYP/C (p=0.014) and HYP (p=0.032) CONCLUSIONS: The results suggest that a 7-day CrM loading phase may acutely improve PP, MP, and VO2 during acute hypoxia exercise performance. Further research should be completed to increase statistical power and to include a normoxic condition following CrM loading. The findings of the present study may benefit collegiate sprint and power athletes who often travel to higher altitudes for competition without sufficient time for acclimatization.

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