Muscle deoxygenation and neuromuscular activation in synergistic muscles during intermittent exercise under hypoxic conditions
Muscle deoxygenation and neuromuscular activation in synergistic muscles during intermittent exercise under hypoxic conditions
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DOI：
10.1038/s41598-019-57099-y
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发表时间：
2020-01-15
影响因子：
4.6
通讯作者：
Akima, Hiroshi
中科院分区：
文献类型：
--
作者：
Yoshiko, Akito;Katayama, Keisho;Akima, Hiroshi
本研究的目的是阐明缺氧对协同股四头肌（QF）肌肉（即，股直肌、股内侧肌、股中间肌和股外侧肌）。10名健康男性进行等长间歇性膝关节伸展运动，右腿在50%的最大自主收缩3分钟，同时吸入常氧[吸入的氧气（O-2）分数= 0.21]或缺氧（吸入的O-2分数= 0.10-0.12）气体混合物。通过组织O-2饱和度（StO（2））测量肌肉脱氧，并通过使用近红外光谱和表面肌电图的QF个体肌肉的表面肌电图信号的均方根（RMS）测量神经肌肉激活。在运动过程中，低氧时StO（2）比常氧时下降得更多，在间歇性伸膝过程中，低氧时QF的单个肌肉的RMS比常氧时增加得更多。缺氧时与常氧时相比，QF各肌的StO（2）和RMS比值无差异。这些研究结果表明，次极量，等距，和间歇性运动在缺氧条件下提高肌肉耗氧量和肌肉活动类似的协同肌肉。
The purpose of this study was to elucidate the effects of hypoxia on deoxygenation and neuromuscular activation in synergistic quadriceps femoris (QF) muscles (i.e., the rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis) during submaximal intermittent knee extension. Ten healthy men performed isometric intermittent knee extension exercises with the right leg at 50% of maximal voluntary contraction for 3 min while inhaling a normoxic [inspired oxygen (O-2) fraction = 0.21] or hypoxic (inspired O-2 fraction = 0.10-0.12) gas mixture. Muscle deoxygenation was measured by tissue O-2 saturation (StO(2)), and neuromuscular activation by root mean square (RMS) of the surface electromyographic signals, from individual muscles of the QF using near-infrared spectroscopy and surface electromyography. StO(2) was decreased more in hypoxia than normoxia during the exercises, and there was a greater increase in RMS during intermittent knee extension in hypoxia than normoxia in individual muscles of the QF. There were no differences in the ratios of StO(2) and RMS in hypoxia compared with normoxia between individual muscles of the QF. These findings suggest that submaximal, isometric, and intermittent exercises in hypoxic conditions enhanced muscle oxygen consumption and muscle activity similarly for synergistic muscles.