PDF(Pubmed)
Abstract：
We examine the impact of the acute manipulation of oxygen availability during discrete phases (active and passive) of a repeated-sprint cycling protocol on performance, physiological, and perceptual responses. On separate days, twelve trained males completed four sets of five 5-s \'all out\' cycle sprints (25-s inter-sprint recovery and 5-min interset rest) in four randomized conditions: normobaric hypoxia (inspired oxygen fraction of 12.9%) applied continuously (C-HYP), intermittently during only the sets of sprints (I-HYPSPRINT) or between-sets recovery periods (I-HYPRECOVERY), or not at all (C-NOR). Peak and mean power output, peripheral oxygen saturation, heart rate, blood lactate concentration, exercise-related sensations, and vastus lateralis muscle oxygenation using near-infrared spectroscopy were assessed. Peak and mean power output was ∼4%-5% lower for C-HYP compared to C-NOR (P ≤ 0.050) and I-HYPRECOVERY (P ≤ 0.027). Peripheral oxygen saturation was lower during C-HYP and I-HYPSPRINT compared with C-NOR and I-HYPRECOVERY during sets of sprints (∼83-85 vs. ∼95%-97%; P < 0.001), while lower values were obtained for C-HYP and I-HYPRECOVERY than C-NOR and I-HYPSPRINT during between-sets rest period (∼84-85 vs. ∼96%; P < 0.001). Difficulty in breathing was ∼21% higher for C-HYP than C-NOR (P = 0.050). Ratings of perceived exertion (P = 0.435), limb discomfort (P = 0.416), heart rate (P = 0.605), blood lactate concentration (P = 0.976), and muscle oxygenation-derived variables (P = 0.056 to 0.605) did not differ between conditions. In conclusion, the method of hypoxic exposure application (continuous vs. intermittent) affects mechanical performance, while internal demands remained essentially comparable during repeated cycle sprints.
摘要：
我们研究了反复冲刺循环协议的离散阶段（主动和被动）中急性氧气可用性操纵对性能的影响，生理,和感性的反应。在不同的日子里，12名受过训练的男性在四个随机条件下完成了4组5个5秒周期冲刺（25秒冲刺间恢复和5分钟间歇休息）：常压低氧（吸入氧气分数为12.9％）连续施加（C-HYP），仅在sprint组（I-HYPSPRINT）或在组之间的恢复期（I-HYPRECOVERY）中间歇性地，或者根本没有（C-NOR）。峰值和平均功率输出，外周血氧饱和度,心率,血乳酸浓度，运动相关的感觉，使用近红外光谱评估了股外侧肌的氧合。C-HYP的峰值和平均功率输出比C-NOR（P≤0.050）和I-HYPRECOVERY（P≤0.027）低4%-5%。C-HYP和I-HYPSPRINT期间的外周血氧饱和度较低，而在两组冲刺期间的C-NOR和I-HYPRECOVERY（〜83-85vs.95%-97%；P<0.001)，而在两组间休息期间，C-HYP和I-HYPRECOVERY的值低于C-NOR和I-HYPSPRINT（〜84-85vs.96%；P<0.001）。C-HYP的呼吸困难比C-NOR高21%(P=0.050)。感知劳累的等级(P=0.435)，肢体不适（P=0.416），心率（P=0.605），血乳酸浓度（P=0.976），和肌肉氧合衍生变量(P=0.056~0.605)在不同条件下没有差异.总之,低氧暴露应用方法(连续与间歇性)影响机械性能，而内部需求在重复周期冲刺期间保持基本可比。
