Hoppeler H
Institute of Anatomy, University of Berne, Switzerland.
Int J Obes Relat Metab Disord. 1999 Apr;23 Suppl 3:S7-10. doi: 10.1038/sj.ijo.0800878.
Endurance power of muscles is determined largely by the capacities to oxidize substrates in mitochondria in the process of making ATP by oxidative phosphorylation. This review explores physiological and morphological factors that may cause limitation of carbohydrate and fat utilization by muscle cells. The pathways for oxygen and substrates converge in muscle mitochondria. In mammals, a structural limitation of carbohydrate and lipid transfer from the microvascular system to muscle cells is reached at a moderate work intensity (that is, at 40-50% of VO2max). At higher work rates intracellular substrate stores must be used for oxidation. Because of the importance of these intracellular stores for aerobic work we find larger intramyocellular substrate stores in endurance trained athletes. The transfer limitations for carbohydrates and lipids on the level of the sarcolemma implies that the design of the respiratory cascade from lungs to muscle mitochondria reflects primarily oxygen demand.
肌肉的耐力在很大程度上取决于线粒体通过氧化磷酸化生成三磷酸腺苷（ATP）过程中氧化底物的能力。本综述探讨了可能导致肌肉细胞碳水化合物和脂肪利用受限的生理和形态学因素。氧气和底物的代谢途径在肌肉线粒体中交汇。在哺乳动物中，在中等工作强度（即最大摄氧量的40 - 50%）时，碳水化合物和脂质从微血管系统向肌肉细胞的转运存在结构限制。在更高的工作强度下，必须利用细胞内底物储备进行氧化。由于这些细胞内储备对有氧运动的重要性，我们发现耐力训练运动员的肌细胞内底物储备更多。肌膜水平上碳水化合物和脂质的转运限制意味着从肺到肌肉线粒体的呼吸级联设计主要反映了氧气需求。
