title: The effects of creatine pyruvate and creatine citrate on performance during high intensity exercise.
abstract: BACKGROUND
  A double-blind, placebo-controlled, randomized study was performed to evaluate the effect of oral creatine pyruvate (Cr-Pyr) and creatine citrate (Cr-Cit) supplementation on exercise performance in healthy young athletes.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Increnovo LLC, 2138 E Lafayette Pl, Milwaukee, WI 53202, USA. ralf.jaeger@increnovo.com.
authors.forename: Ralf
authors.initials: R
authors.lastname: Jäger
authors.forename: Jan
authors.initials: J
authors.lastname: Metzger
authors.forename: Karin
authors.initials: K
authors.lastname: Lautmann
authors.forename: Vladimir
authors.initials: V
authors.lastname: Shushakov
authors.forename: Martin
authors.initials: M
authors.lastname: Purpura
authors.forename: Kurt-Reiner
authors.initials: KR
authors.lastname: Geiss
authors.forename: Norbert
authors.initials: N
authors.lastname: Maassen