Metabolic effects of training in humans: a 31P-MRS study.
The purpose of this study was to determine the feasibility of measuring with 31P nuclear magnetic resonance the effects of an endurance training program on the high-energy phosphate metabolism of exercising human skeletal muscle. The system used included a 1.9-T 30-cm-bore Oxford Systems superconducting magnet, a PhosphoEnergetics spectrometer, and a modified Cybex isokinetic ergometer. Seven healthy human volunteers exercised their wrist flexor muscles 20 min/day 5 days/wk for 8 wk. Testing before and after the training period consisted of a performance test to measure muscle functional capacity and a ramp test to measure the work-energy cost relationship of the exercising muscles. The results indicate that the subjects had a significant increase in their work output on the 10-min performance test after training. They also exhibited an increase in the work-energy cost relationship on the ramp test as indicated by a decrease in peak Pi-to-phosphocreatine ratio and an increase in pH at the same relative power output after training. These results indicate that 1) the training program was sufficient to elicit a training effect and 2) this effect was observed with 31P nuclear magnetic resonance as an increased potential for oxidative metabolism, particularly at the high exercise levels.
Kent-Braun
J A
JA
Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia.
McCully
K K
KK
Chance
B
B
D000328:Adult; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009132:Muscles / Q000378:metabolism* / Q000502:physiology; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D010759:Phosphorus Isotopes
D010710:Phosphates; D010759:Phosphorus Isotopes; D010725:Phosphocreatine