Effect of oral phosphocreatinine on human skeletal muscle shown by in vivo P-31-NMR

We used the non-invasive method of in vivo phosphorus magnetic resonance spectroscopy to investigate the effect of oral administration of phosphocreatinine on muscle energy metabolism during graded work and post-exercise recovery in humans. Phosphocreatinine administration results in a smaller depletion of phosphocreatine at high work rates accompanied by a smaller cytosolic acidification during work and recovery. Our findings suggest that oral phosphocreatinine increases the readily available energy for muscle contraction by interfering directly or indirectly with the reaction equilibria involving phosphocreatine.