Acute Effects of Different Blood Flow Restriction Protocols on Bar Velocity During the Squat Exercise.

Michal Wilk,Robert Trybulski,Grzegorz Wojdala,Petr Stastny,Yuri Campos,Ewelina Lulińska,Adam Zajac,Michal Krzysztofik

doi:10.3389/fphys.2021.652896

Abstract

The main goal of the present study was to evaluate the effects of different blood flow restriction (BFR) protocols (continuous and intermittent) on peak bar velocity (PV) and mean bar velocity (MV) during the squat exercise at progressive loads, from 40 to 90% 1RM. Eleven healthy men (age = 23.4 ± 3.1 years; body mass = 88.5 ± 12.1 kg; squat 1RM = 183.2 ± 30.7 kg; resistance training experience, 5.7 ± 3.6 years) performed experimental sessions once a week for 3 weeks in random and counterbalanced order: without BFR (NO-BFR), with intermittent BFR (I-BFR), and with continuous BFR (C-BFR). During the experimental session, the participants performed six sets of the barbell squat exercise with loads from 40 to 90% 1RM. In each set, they performed two repetitions. During the C-BFR session, the cuffs were maintained throughout the training session. During the I-BFR, the cuffs were used only during the exercise and released for each rest interval. The BFR pressure was set to ∼80% arterial occlusion pressure (AOP). Analyses of variance showed a statistically significant interaction for MV (p < 0.02; η2 = 0.18). However, the post hoc analysis did not show significant differences between particular conditions for particular loads. There was no significant condition × load interaction for PV (p = 0.16; η2 = 0.13). Furthermore, there were no main effects for conditions in MV (p = 0.38; η2 = 0.09) as well as in PV (p = 0.94; η2 = 0.01). The results indicate that the different BFR protocols used during lower body resistance exercises did not reduce peak bar velocity and mean bar velocity during the squat exercise performed with various loads.

Highlights

Blood flow restriction (BFR) is a training method that reduces arterial and venous blood flow during effort (Takano et al, 2005; Loenneke and Pujol, 2009; Scott et al, 2015)
There are different possibilities to use BFR in the training process, such as continuous BFR used during several sets of exercise without releasing the pressure during rest intervals, intermittent BFR used during several sets of an exercise while releasing pressure during the rest interval, and preconditioning BFR used only before exercise (Incognito et al, 2016; Marocolo et al, 2016, 2017, 2018, 2019; Wilk et al, 2018, 2020d,e)
The moderate effect size (ES) in mean bar velocity (MV) was found between NO-BFR vs. continuous BFR (C-BFR) and between intermittent BFR (I-BFR) vs. C-BFR at

Summary

Introduction

Blood flow restriction (BFR) is a training method that reduces arterial and venous blood flow during effort (Takano et al, 2005; Loenneke and Pujol, 2009; Scott et al, 2015). The use of BFR in resistance training increases acute physiological responses such as metabolic stress (Pearson and Hussain, 2015; Teixeira et al, 2018), cell swelling (Loenneke et al, 2012b), and endocrine responses (Takano et al, 2005; Shimizu et al, 2016). Since the level of explosive performance depends on these substrates and metabolic mechanisms (Robergs et al, 1991), the use of BFR may be an effective tool for developing muscular power. In addition to the physiological effects, mechanical factors related to BFR can potentially increase acute physical performance (Rawska et al, 2019; Wilk et al, 2020d,e)

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