Effect of exogenous creatine supplementation on muscle PCr metabolism

Int J Sports Med. 2000 Feb;21(2):139-45. doi: 10.1055/s-2000-11065.


31P NMR was used to assess the influence of two weeks creatine supplementation (21g x d(-1)) on resting muscle PCr concentration, on the rate of PCr repletion (R(depl)), and on the half-time of PCr repletion (t 1/2). Body mass (BM) and volume of body water compartments were also estimated by impedance spectroscopy. Fourteen healthy male subjects (20.8+/-1.9 y) participated in this double-blind study. PCr was measured using a surface coil placed under the calf muscle, at rest and during two exercise bout the duration of which was 1 min. They were interspaced by a recovery of 10 min. The exercises comprised of 50 plantar flexions-extensions against weights corresponding to 40% and 70% of maximal voluntary contraction (MVC), respectively. Creatine supplementation increased resting muscle PCr content by approximately 20% (P= 0.002). R(depl) was also increased by approximately 15% (P< 0.001) and approximately 10% (P = 0.026) during 40% and 70% MVC exercises, respectively. No change was observed in R(repl) and t1/2. BM and body water compartments were not influenced. These results indicate that during a standardized exercise more ATP is synthesized by the CK reaction when the pre-exercise level in PCr is higher, giving some support to the positive effects recorded on muscle performance.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / biosynthesis
  • Adult
  • Body Composition
  • Creatine / pharmacology*
  • Dietary Supplements*
  • Exercise / physiology*
  • Humans
  • Magnetic Resonance Spectroscopy
  • Male
  • Muscle, Skeletal / metabolism*
  • Phosphocreatine / metabolism*
  • Task Performance and Analysis


  • Phosphocreatine
  • Adenosine Triphosphate
  • Creatine