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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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PRONOUNCED MUSCLE DEOXYGENATION DURING SUPRAMAXIMAL EXERCISE UNDER SIMULATED HYPOXIA IN SPRINT ATHLETES |
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Kazuo Oguri1  ,
Hajime Fujimoto2, Hiroyuki Sugimori3, Kei Miyamoto4, Toshiki Tachi1, Sachio
Nagasaki5, Yoshihiro Kato5 and Toshio Matsuoka5 |
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1Faculty of Management, Shizuoka Sangyo University, Japan, 2International Pacific University, Japan, 3Faculty of Education, Gifu University, Japan, 4Department of Reconstructive Surgery, Gifu University School of Medicine, Japan, 5Department of Sports Medicine and Sports Science, Gifu University Graduate School of Medicine, Japan |
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© Journal of Sports Science and Medicine (2008) 7, 512 - 519 Search Google Scholar for Citing Articles |
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| ABSTRACT | |||
| The purpose of this study was to determine whether acute hypoxia
alters the deoxygenation level in vastus lateralis muscle during a 30 s
Wingate test, and to compare the muscle deoxygenation level between sprint
athletes and untrained men. Nine male track sprinters (athletic group, VO2max
62.5 ± 4.1 ml/kg/min) and 9 healthy untrained men (untrained group, VO2max
49.9 ± 5.2 ml·kg-1·min-1) performed a 30 s Wingate
test under simulated hypoxic (FIO2 = 0.164 and PIO2
= 114 mmHg) and normoxic conditions. During the exercise, changes in oxygenated
hemoglobin (OxyHb) in the vastus lateralis were measured using near infrared
continuous wave spectroscopy. Decline in OxyHb, that is muscle deoxygenation,
was expressed as percent change from baseline. Percutaneous arterial oxygen
saturation (SpO2), oxygen uptake (VO2), and ventilation
(VE) were measured continuously. In both groups, there was significantly
greater muscle deoxygenation, lower SpO2, lower peakVO2,
and higher peakVE during supramaximal exercise under hypoxia than under
normoxia, but no differences in peak and mean power output during the exercise.
Under hypoxia, the athletic group experienced significantly greater muscle
deoxygenation, lower SpO2, greater decrement in peakVO2
and increment in peakVE during the exercise than the untrained group. When
the athletic and untrained groups were pooled, the increment of muscle deoxygenation
was strongly correlated with lowest SpO2 in the 30 s Wingate
test under hypoxia. These results suggest that acute exposure to hypoxia
causes a greater degree of peripheral muscle deoxygenation during supramaximal
exercise, especially in sprint athletes, and this physiological response
would be explained mainly by lower arterial oxygen saturation.
Key words: NIRcws, muscle deoxygenation, hypoxic, 30s Wingate test, athletes. |
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