Effects Of Autoregulated Versus Traditional Blood Flow Restriction Training On Neuromuscular Function And Perceived Exertion

Traditional blood flow restriction training (T-BFR) involves static pressure settings during exercise. However, a recent advancement, autoregulated BFR (A-BFR), automatically adjusts the cuff pressure as the muscle activates. PURPOSE: To investigate the acute effects of T-BFR, A-BFR, and no BFR on the rate of perceived exertion (RPE), activation, morphology, oxygen saturation (SO2), and total hemoglobin (THb) of the vastus medialis oblique (VMO). METHODS: Eighteen healthy individuals, aged 24.6 ± 2.3 years, consisting of 9 males and 9 females, completed three randomized treatment-order sessions. Participants performed four sets of bodyweight single-leg wall squats on their dominant leg (40°-45° knee flexion) with 30, 15, 15, and 15 repetitions at 3-sec concentric/eccentric cadence and 30-sec recovery between sets. Participants wore the BFR cuff on the proximal thigh at 60% supine limb occlusion pressure. VMO thickness was measured via ultrasound before and after each session. Wireless electromyography (EMG) and near-infrared spectroscopy (NIRS) sensors were used to evaluate VMO activation, SO2, and THb during the exercise. RPE was recorded at the end of each session. Two-way repeated measures ANOVAs were used for statistical analysis. RESULTS: Significant (p < 0.05) time x treatment interactions and main effects of time and treatment were observed for VMO thickness, SO2, THb, and RPE. VMO thickness increased significantly for A-BFR (29.1 ± 1.9 mm to 33.2 ± 2.1 mm), T-BFR (29.6 ± 1.9 mm to 34.0 ± 2.1 mm), and no BFR (29.3 ± 1.8 mm to 31.2 ± 2.0 mm). SO2 levels decreased significantly for A-BFR (39.7%), T-BFR (34.6%), and no BFR (19.8%), while THb increased significantly by 2.9% for A-BFR, 2.7% for T-BFR, and 1.2% for no BFR. Additionally, RPE significantly (p < 0.05) increased for A-BFR (40.7%), T-BFR (42.0%), and no BFR (43.7%). However, significant (p < 0.05) differences were observed between BFR and no BFR conditions for VMO thickness, SO2, THb, and RPE. No significant (p > 0.05) differences were observed for VMO activation. CONCLUSION: These findings indicate no significant difference between A-BFR and T-BFR, suggesting that autoregulation during BFR did not offer additional benefits during bodyweight single-leg wall squats. Supported by: Supported by MARC-ACSM Early-Stage Investigator Grant