Journal article
Breakpoints in ventilation, cerebral and muscle oxygenation, and muscle activity during an incremental cycling exercise
Frontiers in Physiology, Vol.5
2014
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.
Details
- Title
- Breakpoints in ventilation, cerebral and muscle oxygenation, and muscle activity during an incremental cycling exercise
- Authors/Creators
- S. Racinais (Author/Creator) - Qatar Orthopaedic and Sports Medicine HospitalM. Buchheit (Author/Creator) - Sport Science Department, Myorobie Association, Montvalezan, FranceO. Girard (Author/Creator) - University of Lausanne
- Publication Details
- Frontiers in Physiology, Vol.5
- Publisher
- Frontiers
- Identifiers
- 991005541979007891
- Copyright
- © 2014 Racinais, Buchheit and Girard.
- Murdoch Affiliation
- Murdoch University
- Language
- English
- Resource Type
- Journal article
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- Collaboration types
- Domestic collaboration
- International collaboration
- Citation topics
- 1 Clinical & Life Sciences
- 1.172 Sports Science
- 1.172.648 Exercise Physiology
- Web Of Science research areas
- Physiology
- ESI research areas
- Biology & Biochemistry