ESTIMATION OF MUSCULAR ENERGY METABOLISM DURING EXERCISE AND EFFECTS OF MUSCLE TRAINING STUDIED BY ^<31>P-NMR SPECTROSCOPY.

我们使用^<31 b> P-NMR波谱检查了运动期间肌肉能量代谢的反应和肌肉训练对肌肉能量代谢的影响。结果总结如下：1。在渐进式运动中，细胞内pH值随着工作量的增加而逐渐降低，然后在最大工作量的57%左右（pH值的6.9）时出现快速酸化。细胞内pH值的阈值与综合肌电图和过期气体参数非线性增加检测到的阈值显著相关。在肌肉温度低于正常的情况下，无氧运动时细胞内pH值高于对照组，无氧耐力表现明显下降。这些结果表明，在肌肉温度过低的情况下，糖酵解能量通路受到抑制。相反，在有氧运动前进行热身运动时，细胞内pH值高于对照组。这个结果意味着肌肉的氧化能力通过热身运动得到提高。有氧训练（运动强度为30-40% MVC，频率为4天/周，训练周期为15周）的结果是，在相同的次最大工作量下，肌肉的氧化能力显著提高，表现为Pi/PCr比值降低，细胞内pH升高。同时，耐力表现的改善与肌肉酸化程度的降低是平行的。经过一次力量训练（运动强度最大为10次重复，频率为4天/周，训练周期为5周），肌肉力量输出和无氧耐力时间明显增加。而在磷代谢变化方面，仅出现无氧运动时由于训练导致的%PCr升高。细胞内pH值在训练前和训练后没有差异。这些结果表明，无氧性能的提高可能是由于训练增加了磷，改善了糖酵解能力，或增加了肌肉中肌酸激酶的活性。少

We examined responses in muscular energy metabolism during exercise and effects of muscle training on muscular energy metabolism using ^<31>P-NMR spectroscopy. The results were summarized as follows :1. During a progressive exercise, intracellular pH decreased gradually with an increase of work load, and then a rapid acidification was observed at about 57% of the maximal work load (6.9 of pH value). This threshold in intracellular pH correlated significantly to thresholds detected from non-linear increases in integrated electromyogram and expired gas parameters.2. In a subnormal muscle temperature condition, intracellular pH during an anaerobic exercise showed the higher value than that at a control condition, and the anaerobic endurance performance decreased significantly. These results suggest that glycolytic energy pathway would be inhibited under the subnormal muscle temperature condition. On the contrary, intracellular pH during an aerobic exercise preceded by a warm-up exercise s … More howed the higher value than that of the control condition. This result means that the oxidative capacity in the muscle is improved by performing a warm-up exercise.3. As a result of an aerobic training (the exercise intensity of 30-40% MVC,the frequency of 4 days/week, and the 15 week training period), the oxidative capacity in muscle was significantly improved as shown by a decrease in Pi/PCr ratio and an increase in intracellular pH at the same sub-maximal work load. And also, the improvement of the endurance performance showed to paralleled to lesser degree of the acidification in the muscle.4. As a result of a power training (the exercise intensity of 10 repetition maximum, the frequency of 4 days/week, and the 5 week training period), muscular power output and anaerobic endurance time increased significantly. However, concerning phosphorus metabolic changes, it only occurred that %PCr during the anaerobic exercise increased due to the training. There was no difference in the intracellular pH between the pre- and the post-training. These results suggest that the increase in the anaerobic performance might be attributable to the increase of phosphagen, the improvement of glycolytic capacity, or the increase in creatine kinase activity in the muscle due to the training. Less