Int J Sports Med 1992; 13(4): 313-318
DOI: 10.1055/s-2007-1021273
© Georg Thieme Verlag Stuttgart · New York

Effect of Training on the Calf Muscle Energy Metabolism

A 31P-NMR Study on Four Elite Downhill Skiers Challenged with a Standardized Exercise ProtocolD. Laurent1 , G. Bernús2 , J. Alonso2 , J. F. Lebas1 , C. Arús1 , J. M. González de Suso3 , A. Rossi1
  • 1Institut de Resonance Magnétique en Biologie et Médecine (IRMBM), Université Joseph Fourier, 38041 Grenoble Cedex, France
  • 2Departament de Bioquímica i Biología Molecular, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
  • 3Unitat de Recerca, Centre d'Alt Rendiment (CAR), 08190 Sant Cugat del Vallés, Barcelona, Spain
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Publication History

Publication Date:
14 March 2008 (online)


This study evaluates the effects of a 6 months' training period on the bioenergetics of the calf muscle of elite athletes by means of phosphorus-31 Nuclear Magnetic Resonance Spectroscopy (31P-NMR). Four downhill skiers, belonging to the Spanish National Team, performed a standardized exercise protocol using their right leg inside a wide-bore 2.35 Tesla magnet. The inorganic phosphate/phosphocreatine (Pi/PC) ratio and intracellular pH (pHi) were measured at steady-state during an exercise protocol composed of 5 work levels between 20% and 80% of the maximum voluntary contraction (MVC), before and after the training period. The measured values, which were markedly scattered at the beginning, regrouped after training. This was caused by a shift towards lower Pi/PC ratios and by a lower pHi acidification in three of the four subjects. This result suggests that 31P-NMR is a good tool to evaluate changes in the muscle aerobic capacity of athletes induced by training.