Yeap Ming Wei, Loh Tze Chien, Chong Mee Chee, Yeo Wee Kian, Girard Olivier, Tee Chris Chow Li
Division of Research and Innovation, National Sports Institute of Malaysia, Kuala Lumpur, Malaysia.
Division of Sports Performance, National Sports Institute of Malaysia, Kuala Lumpur, Malaysia.
Int J Sports Physiol Perform. 2024 Sep 4;19(11):1334-1338. doi: 10.1123/ijspp.2024-0083. Print 2024 Nov 1.
We investigated the effects of manipulating running velocity and hypoxic exposure on vastus lateralis muscle oxygenation levels during treadmill running.
Eleven trained male distance runners performed 7 randomized runs at different velocities (8, 10, 12, 14, 16, 18, and 20 km·h-1), each lasting 45 seconds on an instrumented treadmill in normoxia (fraction of inspired oxygen [FiO2] = 20.9%), moderate hypoxia (FiO2 = 16.1%), high hypoxia (FiO2 = 14.1%), and severe hypoxia (FiO2 = 13.0%). Continuous assessment of Tissue Saturation Index (TSI) in the vastus lateralis muscle was conducted using near-infrared spectroscopy. Subsequently, changes in TSI (ΔTSI) data over the final 20 seconds of each run were compared between velocities and conditions.
There was a significant velocity × condition interaction for ΔTSI% (P < .001, ηp2=.19), with a smaller ΔTSI% decline in normoxia compared with high hypoxia and severe hypoxia at 8 km·h-1 (g = 1.30 and 1.91, respectively), 10 km·h-1 (g = 0.75 and 1.43, respectively), and 12 km·h-1 (g = 1.47 and 1.95, respectively) (pooled values for all conditions: P < .037). The ΔTSI% decline increased with each subsequent velocity increment from 8 km·h-1 (-9.2% [3.7%]) to 20 km·h-1 (-22.5% [4.1%]) irrespective of hypoxia severity (pooled values for all conditions: P < .048).
Running at slower velocities in conjunction with high and severe hypoxia reduces vastus lateralis muscle oxygenation levels. Muscle ΔTSI% proves to be a sensitive indicator, underscoring the potential use of near-infrared spectroscopy as a reference index of internal load during treadmill runs.
我们研究了在跑步机跑步过程中，改变跑步速度和低氧暴露对股外侧肌氧合水平的影响。
11名训练有素的男性长跑运动员在装有仪器的跑步机上以不同速度（8、10、12、14、16、18和20 km·h-1）进行7次随机跑步，每次持续45秒，分别处于常氧（吸入氧分数[FiO2]=20.9%）、中度低氧（FiO2 = 16.1%）、高度低氧（FiO2 = 14.1%）和重度低氧（FiO2 = 13.0%）环境中。使用近红外光谱法持续评估股外侧肌的组织饱和度指数（TSI）。随后，比较了每次跑步最后20秒内TSI（ΔTSI）数据在不同速度和条件下的变化。
ΔTSI%存在显著的速度×条件交互作用（P <.001，ηp2 =.19），在8 km·h-1（分别为g = 1.30和1.91）、10 km·h-1（分别为g = 0.75和1.43）和12 km·h-1（分别为g = 1.47和1.95）时，与高度低氧和重度低氧相比，常氧下的ΔTSI%下降幅度较小（所有条件的合并值：P <.037）。无论低氧严重程度如何，随着速度从8 km·h-1（-9.2% [3.7%]）每次递增至20 km·h-1（-22.5% [4.1%]），ΔTSI%下降幅度均增加（所有条件的合并值：P <.048）。
在高度和重度低氧环境下以较慢速度跑步会降低股外侧肌的氧合水平。肌肉ΔTSI%被证明是一个敏感指标，突出了近红外光谱法作为跑步机跑步过程中内部负荷参考指标的潜在用途。
