Bio-energetic changes in human gastrocnemius muscle 1-2 days after strenuous exercise.
[31P]magnetic resonance spectroscopy was used to study the metabolic sequelae of intense muscular activity in gastrocnemius of seven subjects 1-2 days after a 67-mile bicycle ride. The muscle was examined at rest, during a test exercise and during recovery from test exercise. Post-ride and pre-ride results were compared. At rest, the ratio of phosphocreatine to ATP (PCr/ATP) was increased post-ride; during test exercise PCr/(PCr+Pi) was lower post-ride; and the recoveries of PCr, Pi and PCr/(PCr+Pi) after test exercise were delayed, with decreased 'overshoot' of PCr/(PCr+Pi) (which is due to recovery of Pi to below its resting value). Mild mitochondrial damage (perhaps due to exposure to high cytosolic [Pi] during the bicycle ride) may explain some of these results. In contrast to reports of largely eccentric exercise there was no increase in resting Pi/ATP. We have thus demonstrated perturbations of muscle bio-energetics 1-2 days after strenuous exercise, in the absence of convincing enzymological evidence of muscle damage.
Kemp
G J
GJ
MRC Clinical and Biochemical Magnetic Resonance Unit, John Radcliffe Hospital, Oxford, UK.
Taylor
D J
DJ
Radda
G K
GK
Rajagopalan
B
B
D000328:Adult; D001219:Aspartate Aminotransferases / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism / Q000502:physiology; D009132:Muscles / Q000378:metabolism*
D001219:Aspartate Aminotransferases; D003402:Creatine Kinase