운동선수와 일반인의 골격근 pH 및 고에너지 인(P) 대사

Skeletal muscle pH and high energy phosphate metabolism in athletes and sedentary men

The purpose of this study was to evaluate intramuscular pH and the high energy phosphate metabolism in the skeletal muscle between athletes (n=11) and sedentary men (n=11). Exercise protocols were consisted of continuous isometric contractions of Maximal Voluntary Contraction (MVC) 1% and MVC 5%. ³¹P NMR spectroscopy was used for analyzing intramuscular pH and Pi/PCr during exercise. In both groups, intramuscular pH was decreased according to the time course. The lowest intramuscular pH in athletes was observed at 28 min after MVC 1% exercise, which was significantly higher than that of sedentary men (p＜.05), and the reduction rate of pH was about 2.6%. The same results were obtained with MVC 5% exercise. The ratio of Pi to PCr (Pi/PCr) was increased according to the time course in both groups. The highest ratio of Pi/PCr in athletes was observed at 24 min with MVC 1% exercise, which was significantly lower than that of sedentary men (p＜.05). The ratio of Pi/PCr at all-out with MVC 5% exercise was lower than that of resting, which was different from sedentary men. In conclusion, intramuscular pH muscle in athletes was significantly higher and the ratio of Pi/PCr in athletes was significantly lower, than those of sedentary men (p＜.05).