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

Abstract: Leitão, L, Pareja-Blanco, F, Marinho, D, and Neiva, H. Effects of different back squat protocols on prefrontal cortex oxygenation responses. J Strength Cond Res XX(X): 000-000, 2025-The prefrontal cortex (PFC) plays an important role in the execution of the various motor tasks that an athlete performs because the brain is involved in the process of starting and ending every exercise. However, the cerebral oxygenation responses to resistance exercise until muscle failure induced by distinct loads are unclear. Therefore, we examined the PFC oxygenation responses to different loads in the back squat exercise. Eighteen men (4.3 ± 1.4 years of experience, 28.1 ± 3.8 years, 74.8 ± 8.8 kg, 1.78 ± 0.05 m, 14.9 ± 3.9% body fat) performed 3 back squat protocols to task failure with distinct loading conditions: 3, 6, and 10RM. Prefrontal cortex oxygenation (oxygenated-HbO2 and deoxygenated-HHb hemoglobin; total hemoglobin-tHb; and tissue oxygenation index-TOI) was analyzed during the protocols by near-infrared spectroscopy. HbO2 and tHb increased throughout the protocols for all loading conditions (p < 0.01). The 10RM load resulted in decreases in HHb in the last repetition and lower increases in HbO2 and tHB than the other protocols (p < 0.05). By contrast, 3RM induced higher increases in HbO2 and tHb than 6RM and 10RM (p < 0.05). Although HbO2 and tHb increased until failure in all protocols, loads influence the magnitude of PFC oxygenation response. These findings support the role of higher exercise intensities in eliciting central changes in brain activity.