Knuiman Pim, Hopman Maria T E, Wouters Jeroen A, Mensink Marco
Division of Human Nutrition, Wageningen University and Research, Wageningen, Netherlands.
Department of Physiology, Radboud University Medical Centre, Nijmegen, Netherlands.
Front Physiol. 2018 Jan 26;9:28. doi: 10.3389/fphys.2018.00028. eCollection 2018.
Substantial research has been done on the impact of carbohydrate and fat availability on endurance exercise adaptation, though its role in the acute adaptive response to resistance exercise has yet to be fully characterized. We aimed to assess the effects of a pre-resistance exercise isocaloric mixed meal containing different amounts of carbohydrates and fat, on post-resistance exercise gene expression associated with muscle adaptation. Thirteen young (age 21.2 ± 1.6 year), recreationally trained (VO 51.3 ± 4.8 ml/kg/min) men undertook an aerobic exercise session of 90-min continuous cycling (70% VO) in the morning with pre- and post-exercise protein ingestion (10 and 15 g casein in a 500 ml beverage pre- and post-exercise, respectively). Subjects then rested for 2 h and were provided with a meal consisting of either 3207 kJ; 52 g protein; 51 g fat; and 23 g carbohydrate (FAT) or 3124 kJ; 53 g protein; 9 g fat; and 109 g carbohydrate (CHO). Two hours after the meal, subjects completed 5 × 8 repetitions (80% 1-RM) for both bilateral leg press and leg extension directly followed by 25 g of whey protein (500 ml beverage). Muscle biopsies were obtained from the at baseline (morning) and 1 and 3 h post-resistance exercise (afternoon) to determine intramuscular mRNA response. Muscle glycogen levels were significantly decreased post-resistance exercise, without any differences between conditions. Plasma free fatty acids increased significantly after the mixed meal in the FAT condition, while glucose and insulin were higher in the CHO condition. However, PDK4 mRNA quantity was significantly higher in the FAT condition at 3 h post-resistance exercise compared to CHO. HBEGF, INSIG1, MAFbx, MURF1, SIRT1, and myostatin responded solely as a result of exercise without any differences between the CHO and FAT group. FOXO3A, IGF-1, PGC-1α, and VCP expression levels remained unchanged over the course of the day. We conclude that mRNA quantity associated with muscle adaptation after resistance exercise is not affected by a difference in pre-exercise nutrient availability. PDK4 was differentially expressed between CHO and FAT groups, suggesting a potential shift toward fat oxidation and reduced glucose oxidation in the FAT group.
关于碳水化合物和脂肪供应对耐力运动适应的影响已开展了大量研究，但其在抗阻运动急性适应性反应中的作用尚未完全明确。我们旨在评估抗阻运动前摄入含不同碳水化合物和脂肪量的等热量混合餐，对与肌肉适应相关的抗阻运动后基因表达的影响。13名年轻男性（年龄21.2±1.6岁，进行休闲训练，VO₂max为51.3±4.8 ml/kg/min）于早晨进行了90分钟的持续骑行有氧运动（70%VO₂max），运动前后均摄入蛋白质（运动前和运动后分别在500毫升饮料中摄入10克和15克酪蛋白）。受试者随后休息2小时，之后提供一顿餐食，餐食包含3207千焦能量、52克蛋白质、51克脂肪和23克碳水化合物（FAT组），或者3124千焦能量、53克蛋白质、9克脂肪和109克碳水化合物（CHO组）。用餐2小时后，受试者针对双侧腿举和腿部伸展完成5组每组8次重复动作（80%1-RM），随后立即摄入25克乳清蛋白（500毫升饮料）。在基线（早晨）以及抗阻运动后1小时和3小时（下午）从股外侧肌获取肌肉活检样本，以确定肌内mRNA反应。抗阻运动后肌肉糖原水平显著降低，各条件之间无差异。FAT组混合用餐后血浆游离脂肪酸显著增加，而CHO组的葡萄糖和胰岛素水平更高。然而，与CHO组相比，抗阻运动后3小时FAT组的PDK4 mRNA量显著更高。HBEGF、INSIG1、MAFbx、MURF1、SIRT1和肌生成抑制素仅因运动而产生反应，CHO组和FAT组之间无差异。FOXO3A、IGF-1、PGC-1α和VCP表达水平在一天中保持不变。我们得出结论，抗阻运动后与肌肉适应相关的mRNA量不受运动前营养供应差异的影响。CHO组和FAT组之间PDK4表达存在差异，表明FAT组可能向脂肪氧化转变且葡萄糖氧化减少。
