Effects of Different Back Squat Protocols on Prefrontal Cortex Oxygenation Responses.

Area of Science:

• Exercise Physiology
• Neuroscience
• Sports Science

Background:

• The prefrontal cortex (PFC) is crucial for motor task execution and exercise initiation/cessation.
• Cerebral oxygenation responses to resistance exercise to failure with varying loads remain unclear.

Purpose of the Study:

• To investigate prefrontal cortex (PFC) oxygenation responses during back squat exercise to task failure under different loading conditions (3, 6, and 10 repetition maximum - RM).

Main Methods:

• Eighteen men completed back squat protocols to task failure using 3RM, 6RM, and 10RM loads.
• Near-infrared spectroscopy (NIRS) was used to measure PFC oxygenation, including oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HHb), total hemoglobin (tHb), and tissue oxygenation index (TOI).

Main Results:

• Oxygenated hemoglobin (HbO2) and total hemoglobin (tHb) increased significantly (p < 0.01) throughout all protocols.
• The 3RM protocol induced greater increases in HbO2 and tHb compared to 6RM and 10RM protocols (p < 0.05).
• The 10RM load resulted in decreased HHb in the final repetition and smaller increases in HbO2 and tHb than other protocols (p < 0.05).

Conclusions:

• Back squat exercise to failure increases PFC oxygenation, with higher exercise intensities (lower RM loads) eliciting a more pronounced response.
• The findings suggest that exercise intensity influences the magnitude of central changes in brain activity during resistance exercise.