MRS quantifies muscle metabolism in athletes

MR spectroscopy can be used to assess the metabolic status of elite athletes' muscle fibers. This type of metabolic information might be useful for assessing training conditions or revealing individual predispositions to particular types of muscular activity, according to research presented Friday at the ECR.

Dr. Roberto Pastorino and colleagues from the department of experimental medicine at the University of Genoa, Italy, used phosphorus MR spectroscopy to analyze the concentrations of quadriceps muscle metabolites in elite track and field athletes trained in long-distance and sprint running.

The researchers measured adenosine triphosphate (ATP), phosphocreatine (PCr), and inorganic phosphate (Pi) and their reciprocal ratio in 27 athletes, whose ages ranged between 18 and 35. Fifteen subjects were sprint runners, five were middle-distance runners, and seven were long-distance or marathon runners.

MRS was performed with a heart-liver spectroscopy coil and spin-echo sequences for a 2D-CSI technique, characterized by repetition times of 323 msec and echo times of 3 msec, with a total acquisition time of nearly 17 minutes.

The mean value of PCr/ATP measured in sprint runners was 3.2, while PCr/ATP in long-distance runners was 4.2. Other metabolites did not show any agreement with the running specialty. This disparity between long-distance runners and sprinters might be indicative of fiber type differences developed by good training, Pastorino said.

"Phosphocreatine is more present in long-distance runners because they process their energy differently from sprinters, who use a higher metabolism without lactic acid protection," he said.