Breakpoints in ventilation, cerebral and muscle oxygenation, and muscle activity during an incremental cycling exercise.

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Version: Final published version
Serval ID
serval:BIB_91227197BDF4
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Breakpoints in ventilation, cerebral and muscle oxygenation, and muscle activity during an incremental cycling exercise.
Journal
Frontiers in Physiology
Author(s)
Racinais S., Buchheit M., Girard O.
ISSN
1664-042X (Electronic)
ISSN-L
1664-042X
Publication state
Published
Issued date
2014
Peer-reviewed
Oui
Volume
5
Pages
142
Language
english
Notes
Publication types: Journal Article Publication Status: epublish
Abstract
The aim of this study was to locate the breakpoints of cerebral and muscle oxygenation and muscle electrical activity during a ramp exercise in reference to the first and second ventilatory thresholds. Twenty-five cyclists completed a maximal ramp test on an electromagnetically braked cycle-ergometer with a rate of increment of 25 W/min. Expired gazes (breath-by-breath), prefrontal cortex and vastus lateralis (VL) oxygenation [Near-infrared spectroscopy (NIRS)] together with electromyographic (EMG) Root Mean Square (RMS) activity for the VL, rectus femoris (RF), and biceps femoris (BF) muscles were continuously assessed. There was a non-linear increase in both cerebral deoxyhemoglobin (at 56 ± 13% of the exercise) and oxyhemoglobin (56 ± 8% of exercise) concomitantly to the first ventilatory threshold (57 ± 6% of exercise, p > 0.86, Cohen's d < 0.1). Cerebral deoxyhemoglobin further increased (87 ± 10% of exercise) while oxyhemoglobin reached a plateau/decreased (86 ± 8% of exercise) after the second ventilatory threshold (81 ± 6% of exercise, p < 0.05, d > 0.8). We identified one threshold only for muscle parameters with a non-linear decrease in muscle oxyhemoglobin (78 ± 9% of exercise), attenuation in muscle deoxyhemoglobin (80 ± 8% of exercise), and increase in EMG activity of VL (89 ± 5% of exercise), RF (82 ± 14% of exercise), and BF (85 ± 9% of exercise). The thresholds in BF and VL EMG activity occurred after the second ventilatory threshold (p < 0.05, d > 0.6). Our results suggest that the metabolic and ventilatory events characterizing this latter cardiopulmonary threshold may affect both cerebral and muscle oxygenation levels, and in turn, muscle recruitment responses.
Pubmed
Web of science
Open Access
Yes
Create date
29/01/2015 20:30
Last modification date
20/08/2019 14:54
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