School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia.
Institute of Sport Sciences of the University of Lausanne, University of Lausanne, Lausanne, Switzerland.
Eur J Sport Sci. 2022 Dec;22(12):1877-1888. doi: 10.1080/17461391.2021.2002951. Epub 2021 Dec 2.
This study quantified performance and physiological responses during multi-set resistance exercise to failure at light moderate loads in normoxia and systemic hypoxia. On separate visits, fifteen resistance-trained adults performed barbell curl exercise trials (6 sets to failure, 2 min rest between sets) in four separate randomised conditions; i.e. in normoxia at 380 m above sea level or systemic hypoxia at ∼3800 m simulated altitude (inspired oxygen fraction = 20.9% and 12.9%, respectively) combined with two different intensity levels (30% and 70% of 1 repetition maximal or 1RM). Muscle activation (root mean square value calculated from surface electromyography) and oxygenation (integrated-tissue saturation index derived from near-infrared spectroscopy) were monitored for the muscle. The total number of repetitions before failure at 30% 1RM (122 ± 5 . 131 ± 5; = 0.021), but not 70% 1RM (39 ± 1 . 41 ± 2; = 0.313), was lower in hypoxia compared to normoxia. Root mean square activity of the muscle was higher for 70% 1RM compared to 30% 1RM ( < 0.001), while the increase in muscle activation from the first to the last set ( < 0.001) occurred independently of altitude ( > 0.158). Deoxygenation and reoxygenation responses were higher under hypoxic normoxic conditions at 70% 1 RM ( = 0.013 and = 0.015) but not 30% 1RM ( = 0.528 and = 0.384). During upper-limb multi-set resistance exercise to failure, exposure to acute normobaric hypoxia negatively impacts performance at light, but not moderate, loads. Overall, external resistance has more profound effects on physiological strain than hypoxic exposure . The addition of acute systemic hypoxia negatively affects work performed at low, but not moderate, loads during upper-limb resistance exercise to failure.Hypoxic exposure, however, does not fundamentally alter muscle activation and oxygenation patterns.Muscle activation and oxygenation responses in turn are more largely influenced by load lifted.
这项研究量化了在常氧和全身缺氧条件下轻中度负荷下多组抗阻运动至力竭时的表现和生理反应。在单独的访问中，十五名经过力量训练的成年人在四个单独的随机条件下进行杠铃弯举运动试验（6 组至力竭，每组之间休息 2 分钟）；即在海拔 380 米的常氧或模拟海拔 3800 米的全身缺氧（吸入氧分数分别为 20.9%和 12.9%），并结合两种不同的强度水平（30%和 70%的 1 次重复最大或 1RM）。监测肌肉的肌肉激活（表面肌电图计算的均方根值）和氧合（近红外光谱衍生的组织整体饱和度指数）。在 30%1RM（122±5.131±5；=0.021）时，与常氧相比，全身缺氧时失败前的总重复次数较低，但在 70%1RM 时则不然（39±1.41±2；=0.313）。与 30%1RM 相比，70%1RM 时的肌肉均方根活性更高（<0.001），而从第一组到最后一组的肌肉激活增加（<0.001）独立于海拔（>0.158）。在 70%1RM 时，缺氧常氧条件下的去氧和再氧合反应更高（=0.013 和=0.015），但在 30%1RM 时则不然（=0.528 和=0.384）。在上肢多组抗阻运动至力竭时，急性常压低氧暴露会对轻负荷但不是中负荷的运动表现产生负面影响。总的来说，外部阻力比低氧暴露对生理负荷的影响更大。在失败的上肢抗阻运动中，急性全身低氧的加入会对低负荷但不是中负荷的运动产生负面影响。然而，低氧暴露并没有从根本上改变肌肉激活和氧合模式。肌肉激活和氧合反应在很大程度上受举起的负荷影响。
