title: Creatine supplementation--part II: in vivo magnetic resonance spectroscopy.
abstract: OBJECTIVE
  Our purpose was to study effects of creatine (Cr) supplementation on muscle metabolites noninvasively by means of magnetic resonance spectroscopy (MRS) before and after supplementation with Cr or placebo.
  
  
  METHODS
  1H-MRS was used in a comprehensive, double-blind, cross-over study in 10 volunteers to measure Cr in m. tibialis anterior and m. rectus femoris at rest. PCr/ATP was observed in m. quadriceps femoris by 31P-MRS at rest and after exercise.
  
  
  RESULTS
  A significant increase in total Cr was observed with Cr intake in m. tibialis anterior (+9.6 +/- 1.7%, P = 0.001) and in m. rectus femoris (+18.0 +/- 1.8%, P < 0.001). PCr/ATP showed a significant increase (+23.9 +/- 2.3%, P < 0.001) in m. quadriceps femoris at rest with Cr supplementation. Post-Cr supplementation recovery rates from exercise were significantly lower (k = 0.029 s(-1), P < 0.01) compared with postplacebo consumption (k = 0.034 s(-1)) and presupplementation (k = 0.037 s(-1)). However, higher levels of PCr/ATP at rest compensate for this reduction of the recovery rate after Cr supplementation. The increase of PCr/ATP determined by 31P-MRS correlates with the increase of Cr observed by 1H-MRS (r = 0.824, P < 0.001).
  
  
  CONCLUSIONS
  Noninvasive observation of Cr and PCr after Cr supplementation shows an increase in a muscle specific manner. Higher preexercise levels of PCr/ATP at rest compensate for significantly slower recovery rates of PCr/ATP after Cr supplementation.
authors.affiliation: Department of Clinical Research, University of Bern, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Kreis
authors.forename: M
authors.initials: M
authors.lastname: Kamber
authors.forename: M
authors.initials: M
authors.lastname: Koster
authors.forename: J
authors.initials: J
authors.lastname: Felblinger
authors.forename: J
authors.initials: J
authors.lastname: Slotboom
authors.forename: H
authors.initials: H
authors.lastname: Hoppeler
authors.forename: C
authors.initials: C
authors.lastname: Boesch
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D003401:Creatine / Q000008:administration & dosage* / Q000494:pharmacology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D013177:Sports
chemical_list: D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D003401:Creatine