title: Noninvasive measurement of muscle high-energy phosphates and glycogen concentrations in elite soccer players by 31P- and 13C-MRS.
abstract: OBJECTIVE
  The purpose of this study was to measure noninvasively the absolute concentrations of muscle adenosine triphosphate [ATP], phosphocreatine [PCr], inorganic phosphate (Pi), and glycogen [Gly] of elite soccer players.
  
  
  METHODS
  Magnetic resonance spectroscopy (31P- and 13C-MRS) was used to measure the concentrations of metabolites in the calf muscles of 18 young male players [age = 17.5 +/- 1.0 (SD) yr].
  
  
  RESULTS
  Average muscle [PCr] and [ATP] were 17.8 +/- 3.3 and 6.0 +/- 1.2 mmol x (kg wet weight)(-1), respectively. The ratios of Pi/PCr and PCr/ATP were 0.15 +/- 0.05 and 3.00 +/- 0.26, respectively. The muscle [Gly] was 144 +/- 54 mmol x (kg wet weight)(-1). There was a high correlation (r = 0.93, P < 0.0001) between muscle ATP and PCr concentrations, but there was no correlation between [Gly] and [PCr] or [ATP]. The concentrations of the different metabolites determined in the present study with noninvasive MRS methods were within the ranges of values reported in human muscle from biochemical analysis of muscle biopsies.
  
  
  CONCLUSIONS
  MRS methods can be utilized to assess noninvasively the muscle energetic status of elite soccer players during a soccer season. The high correlation between ATP and PCr might be indicative of fiber type differences in the content of these two metabolites.
authors.affiliation: Department of Biochemistry and Molecular Biology, University Autonoma of Barcelona, Spain. ricosanzj@missouri.edu
authors.forename: J
authors.initials: J
authors.lastname: Rico-Sanz
authors.forename: M
authors.initials: M
authors.lastname: Zehnder
authors.forename: R
authors.initials: R
authors.lastname: Buchli
authors.forename: G
authors.initials: G
authors.lastname: Kühne
authors.forename: U
authors.initials: U
authors.lastname: Boutellier
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis*; D000293:Adolescent; D001706:Biopsy; D001835:Body Weight; D002247:Carbon Isotopes; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D006003:Glycogen / Q000032:analysis*; D006801:Humans; D007866:Leg; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry*; D010710:Phosphates / Q000032:analysis*; D010725:Phosphocreatine / Q000032:analysis*; D010759:Phosphorus Isotopes; D015203:Reproducibility of Results; D012916:Soccer / Q000502:physiology
chemical_list: D002247:Carbon Isotopes; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D010710:Phosphates; D010759:Phosphorus Isotopes; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D006003:Glycogen