Cerebral Regulation in Different Maximal Aerobic Exercise Modes.

Area of Science:

• Exercise Physiology
• Neuroscience
• Sports Science

Background:

• Understanding cerebral and peripheral responses during different aerobic exercise modes is crucial for optimizing training and performance.
• Previous research has not fully elucidated the simultaneous cerebral and peripheral physiological adaptations during VO2MAX-matched exercise intensities.
• Investigating differences between controlled-pace incremental tests and self-paced time trials provides insight into central and peripheral regulation during exertion.

Purpose of the Study:

• To compare cerebral oxygenation (COX), muscular oxygenation (MOX), and ratings of perceived exertion (RPE) between a maximal incremental test (MIT) and a 4 km time trial (TT4km) in cyclists.
• To examine primary motor cortex (PMC) electroencephalography (EEG) and electromyography (EMG) responses during VO2MAX-matched exercise modes.
• To determine if motor output and effort tolerance are similar at the end of different aerobic exercise protocols despite varying physiological disturbances.

Main Methods:

• Nine cyclists (VO2MAX: 57.5 ± 6.2 ml·kg(-1)·min(-1)) completed a controlled-pace MIT and a self-paced TT4km.
• Cerebral (PFC) and muscular (VL) oxygenation were measured using near-infrared spectroscopy (NIRS) to assess oxy- (O2Hb) and deoxy-hemoglobin (HHb) changes.
• Primary motor cortex (PMC) EEG, vastus lateralis (VL) and rectus femoris EMG, power output, cardiopulmonary responses, and RPE were recorded throughout both exercise modes.

Main Results:

• Similar motor output (EMG, power output) was observed from 70% of the duration in both MIT and TT4km.
• TT4km exhibited greater muscle deoxygenation (↓ MOX) and cardiopulmonary responses before the 70% duration mark compared to MIT.
• Cerebral oxygenation (↓ O2Hb) was lower in TT4km at 20-60% of the duration but higher at 100% compared to MIT, while PMC EEG alpha wave activity remained constant with higher values in TT4km.

Conclusions:

• Despite different physiological disturbances throughout the exercise, similar motor output and effort tolerance are achieved in the final stages of VO2MAX-matched aerobic exercises.
• Preserved primary motor cortex activation suggests a central regulatory mechanism coordinating exercise responses across different aerobic exercise modalities.
• The findings highlight the complex interplay between central and peripheral factors in regulating exercise intensity and tolerance.