在下肢疲劳性肌肉运动时暴露于常压低氧下的神经肌肉和肌肉组织血液动力学反应。
Neuromuscular and Muscle Tissue Hemodynamic Responses When Exposed to Normobaric Hypoxia during Lower-Body Fatiguing Muscle Actions.
机构信息
Robbins College of Health and Human Sciences, Department of HHPR, Baylor University, USA.
Interdisciplinary Health Sciences PhD Program, Department of Kinesiology, The University of Texas at El Paso, El Paso, TX, USA.
出版信息
J Musculoskelet Neuronal Interact. 2023 Mar 1;23(1):26-35.
OBJECTIVES
This study examined effects of acute hypoxia on the neuromuscular responses (electromyographic (EMG) amplitude and EMG frequency) and localized muscle tissue oxygenated hemoglobin (oxygenated hemoglobin (Oxy), deoxygenated hemoglobin (Deoxy), total hemoglobin (Total), and muscle tissue oxygenation saturation (StO) during the process of fatigue.
METHODS
Fifteen male participants (21.4±2.8yr) performed leg extension repetitions to failure at 70% 1-repetition maximum until volitional exhaustion under Normoxic (FiO:21%) and Hypoxic (FiO:12.9%) conditions. Electromyographic amplitude, EMG frequency, Oxy, Deoxy, Total, and StO were measured from the vastus lateralis at Initial, 20, 40, 60, 80, and 100% of the repetitions to failure.
RESULTS
There was no significant difference in the patterns of responses for EMG amplitude, Oxy, or Deoxy between Normoxia and Hypoxia. For EMG frequency, Hypoxia was greater than Normoxia and decreased with fatigue. Total and StO were greater under Normoxia compared to Hypoxia. The patterns of responses for EMG amplitude, Deoxy, and Total increased throughout the repetitions to failure. Oxy and StO exhibited decreases throughout the repetitions to failure for Normoxic and Hypoxic conditions.
CONCLUSION
The EMG and oxygenation measurements non-invasively suggest a sympathoexcitatory response (indicated by EMG frequency) and provided complimentary information regarding the process of fatigue in normoxic and hypoxic states.
目的
本研究旨在探讨急性低氧对神经肌肉反应（肌电图（EMG）幅度和 EMG 频率）以及局部肌肉组织氧合血红蛋白（氧合血红蛋白（Oxy）、去氧血红蛋白（Deoxy）、总血红蛋白（Total）和肌肉组织氧饱和度（StO）的影响，在疲劳过程中。
方法
15 名男性参与者（21.4±2.8 岁）在常氧（FiO：21%）和低氧（FiO：12.9%）条件下，以 70%的 1 次重复最大量进行腿伸重复至疲劳，直至达到自愿衰竭。从股外侧肌在初始时测量 EMG 幅度、EMG 频率、Oxy、Deoxy、Total 和 StO，在 20%、40%、60%、80%和 100%的重复至疲劳。
结果
在 EMG 幅度、Oxy 或 Deoxy 的反应模式方面，常氧和低氧之间没有显著差异。对于 EMG 频率，低氧时大于常氧，并随疲劳而降低。与低氧相比，常氧时 Total 和 StO 更高。在重复至疲劳的过程中，EMG 幅度、Deoxy 和 Total 的反应模式增加。Oxy 和 StO 在常氧和低氧条件下的重复至疲劳过程中均呈下降趋势。
结论
肌电图和氧合测量无创地提示交感神经兴奋反应（以 EMG 频率表示），并提供了关于常氧和低氧状态下疲劳过程的补充信息。
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