Melissa L, MacDougall J D, Tarnopolsky M A, Cipriano N, Green H J
Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
Med Sci Sports Exerc. 1997 Feb;29(2):238-43. doi: 10.1097/00005768-199702000-00012.
This study examined whether training under normobaric hypoxic conditions (simulating medium level altitude) would enhance physical performance and selected muscle adaptations over and above that which occurs with normoxic training. Ten healthy males (19-25 yr) underwent 8 wk of unilateral cycle ergometry training so that one leg was trained while breathing an inspirate of 13.5% O2 and the other while breathing normal ambient air. Pre- and post-training measurements included single leg VO2max and time to fatigue at 95% VO2max. Needle biopsies from quadriceps were assayed for oxidative and glycolytic enzyme activity and analyzed for capillary density, fiber area, % fiber type, and mitochondrial and lipid volume density. VO2max, time to fatigue, citrate synthase (CS), succinate dehydrogenase, and phosphofructokinase activity increased significantly (P > 0.05) in both legs following training. The increase in CS activity in the hypoxically trained leg was also significantly greater than that in the normoxically trained leg. It thus appears that training under moderate normobaric hypoxic conditions enhances muscle citrate synthase activity to a greater extent than training under normoxic conditions.
本研究探讨在常压低氧条件下（模拟中等海拔高度）进行训练，是否会比在常氧训练基础上进一步提高身体机能，并引发特定的肌肉适应性变化。十名健康男性（19 - 25岁）接受了为期8周的单侧蹬车测力训练，即一条腿在吸入含13.5%氧气的气体时进行训练，另一条腿在呼吸正常环境空气时进行训练。训练前后的测量指标包括单腿最大摄氧量（VO2max）以及在95% VO2max强度下的疲劳时间。对股四头肌进行针刺活检，检测氧化酶和糖酵解酶活性，并分析毛细血管密度、纤维面积、纤维类型百分比以及线粒体和脂质体积密度。训练后，双腿的VO2max、疲劳时间、柠檬酸合酶（CS）、琥珀酸脱氢酶和磷酸果糖激酶活性均显著增加（P > 0.05）。低氧训练腿的CS活性增加也显著大于常氧训练腿。因此，在中等常压低氧条件下进行训练，似乎比在常氧条件下训练能更大程度地提高肌肉柠檬酸合酶活性。
