Abstract

The time course of phosphocreatine (PC) hydrolysis in humans was mesured by 31P-NMR spectroscopy (31-P-NMRS) with a time resolution of 10.8 s in the gastrocnemius muscle and a relationship between muscle 02 consumption (VO2) and (PC) was derived from a bioenergetic model. This allowed a direct estimate of the halftime of the intracellular VO2 kinetics (t1/2 VO2) of the contracting human gastrocnemius in aerobic conditions. t1/2 VO2 was found to be ca. 16 s and independent of the work load. This value corresponds to the shortest t1/2 VO2 determined at the mouth of the subject in the absence of lactate accumulation in the rest to work transient. t1/2 VO2 may now be assessed in man at low muscle temperatures. To this aim a procedure was developed allowing corrections of the 31-P-NMR spectra based on the muscle temperature profiles obtained by a simultaneously acquired proton image. Verf.-Referat