Effects of oral creatine-pyruvate supplementation in cycling performance.
A double-blind study was performed to evaluate the effects of oral creatine-pyruvate administration on exercise performance in well-trained cyclists. Endurance and intermittent sprint performance were evaluated before (pretest) and after (posttest) one week of creatine-pyruvate intake (Cr(pyr), 2 x 3.5 g x d-1, n = 7) or placebo (PL, n = 7). Subjects first performed a 1-hour time trial during which the workload could be adjusted at 5-min intervals. Immediately they did five 10-sec sprints interspersed by 2-min rest intervals. Tests were performed on an individual race bicycle that was mounted on an ergometer. Steady-state power production on average was about 235-245 W, which corresponded to blood lactate concentrations of 4-5 mmol x l -1 and heart rate in the range of 160-170 beats x min -1. Power outputs as well as blood lactate levels and heart rates were similar between Cr(pyr) and PL at all times. Total work performed during the 1-h trial was 872 +/- 44 KJ in PL versus 891 +/- 51 KJ in CR pyr. During the intermittent sprint test power peaked at about 800-1000 watt within 2-3 sec, decreasing by 15-20 % towards the end of each sprint. Peak and mean power outputs were similar between groups at all times. Peak lactate concentrations after the final sprint were approximately 11 mmol x l -1 in both groups during both the pretest and the posttest. It is concluded that one week of creatine-pyruvate supplementation at a rate of 7 g x d -1 does not beneficially impact on either endurance capacity or intermittent sprint performance in cyclists.
Van Schuylenbergh
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R
Exercise Physiology and Biomechanics Laboratory, Department of Kinesiology, Faculty of Physical Education and Physiotherapy, Katholieke Universiteit Leuven, Tervuursevest 101, B-3001 Leuven, Belgium.
Van Leemputte
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M
Hespel
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P
D001642:Bicycling / Q000502:physiology*; D003401:Creatine / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005080:Exercise Test; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D019289:Pyruvic Acid / Q000494:pharmacology*; D013647:Task Performance and Analysis
D019344:Lactic Acid; D019289:Pyruvic Acid; D003401:Creatine