The effects of creatine pyruvate and creatine citrate on performance during high intensity exercise

Performance during intermittent handgrip exercise of maximal intensity was evaluated before (pretest) and after (posttest) 28 days of Cr-Pyr (5 g/d, n = 16), Cr-Cit (5 g/d, n = 16) or placebo (pla, 5 g/d, n = 17) intake. Subjects performed ten 15-sec exercise intervals, each followed by 45 sec rest periods.Cr-Pyr (p < 0.001) and Cr-Cit (p < 0.01) significantly increased mean power over all intervals. Cr-Cit increased force during the first and second interval (p < 0.01) compared to placebo. The effect of Cr-Cit on force decreased over time and the improvement was not significant at the sixth and ninth interval, whereas Cr-Pyr significantly increased force during all intervals (p < 0.001). Cr-Pyr (p < 0.001) and Cr-Cit (p < 0.01) resulted in an increase in contraction velocity, whereas only Cr-Pyr intake significantly (p < 0.01) increased relaxation velocity. Oxygen consumption measured during rest periods significantly increased with Cr-Pyr (p < 0.05), whereas Cr-Cit and placebo intake did not result in significant improvements.It is concluded that four weeks of Cr-Pyr and Cr-Cit intake significantly improves performance during intermittent handgrip exercise of maximal intensity and that Cr-Pyr might benefit endurance, due to enhanced activity of the aerobic metabolism.Creatine monohydrate supplementation has been found to enhance high intensity intermittent athletic performance [1]. Long-term creatine supplementation increases the effects of resistance training on muscle volume, strength and power [2,3]. Short-term creatine supplementation results in an increase of muscle force and power output during intermittent exercise, even in the absence of resistance training [4,5]. Facilitated muscle phosphocreatine resynthesis [6] and more rapid and efficient recovery periods [5,7] have been stated as proposed mechanisms for this ergogenic effect. However, a majority of studies suggest that creatine supplementation does not improve endurance exercise capacity [8,9]. The ef