Kuno S, Takahashi H, Fujimoto K, Akima H, Miyamaru M, Nemoto I, Itai Y, Katsuta S
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Japan.
Eur J Appl Physiol Occup Physiol. 1995;70(4):301-4. doi: 10.1007/BF00865026.
Very little has been reported on muscle energetics during exercise in adolescents. This is attributable to the difficulty of subjecting children to muscle biopsy. The purpose of this study was to investigate the characteristics of muscle metabolism during exercise in vivo in adolescents by comparing firstly, with adults and secondly, the differences resulting from physical activity using phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy. The subjects were boys aged 12 to 15 years, comprising 21 trained boys and 23 control boys, and 6 adults controls. The ratio of phosphocreatine (PCr):(PCr + P(i)), where P(i) is inorganic phosphate intracellular pH at exhaustion and the time constant of PCr during recovery were measured in all the subjects using 31P NMR. Both groups of children showed higher values of PCr:(PCr + P(i)) and intracellular pH at exhaustion than did the adult control group (P < 0.01 or P < 0.05). However, no significant differences were found between the trained boys and the control boys with respect to PCr:(PCr + P(i)) and intracellular pH at exhaustion. On the other hand, we found the same values for PCr time constant in all groups. This result suggested no differences of the muscle oxidative capacity between children and adults. We concluded that the adolescents, aged 12 to 15 years in both the trained and control groups, had less glycolytic ability during exercise than the adults.
关于青少年运动期间肌肉能量代谢的报道非常少。这是由于让儿童接受肌肉活检存在困难。本研究的目的是通过首先与成年人比较，其次使用磷-31核磁共振（31P NMR）光谱研究体育活动导致的差异，来调查青少年体内运动期间肌肉代谢的特征。受试者为12至15岁的男孩，包括21名受过训练的男孩和23名对照男孩，以及6名成年对照组。使用31P NMR在所有受试者中测量磷酸肌酸（PCr）：（PCr + P(i)）的比率，其中P(i)是细胞内无机磷酸盐，在力竭时的细胞内pH值以及恢复期间PCr的时间常数。两组儿童在力竭时的PCr：（PCr + P(i)）和细胞内pH值均高于成年对照组（P < 0.01或P < 0.05）。然而，在受过训练的男孩和对照男孩之间，关于力竭时的PCr：（PCr + P(i)）和细胞内pH值未发现显著差异。另一方面，我们发现所有组的PCr时间常数相同。该结果表明儿童和成年人之间的肌肉氧化能力没有差异。我们得出结论，12至15岁的青少年，无论是训练组还是对照组，在运动期间的糖酵解能力都低于成年人。
