Myoelectric Activity and Fatigue in Low-Load Resistance Exercise With Different Pressure of Blood Flow Restriction: A Systematic Review and Meta-Analysis

Abstract

Background: Low-load resistance exercise (LL-RE) with blood flow restriction (BFR) promotes increased metabolic response and fatigue, as well as more pronounced myoelectric activity than traditional LL-RE. Some studies have shown that the relative pressure applied during exercise may have an effect on these variables, but existing evidence is contradictory.Purpose: The aim of this study was to systematically review and pool the available evidence on the differences in neuromuscular and metabolic responses at LL-RE with different pressure of BFR.Methods: The systematic review and meta-analysis was reported according to PRISMA items. Searches were performed in the following databases: CINAHL, PubMed, Scopus, SPORTDiscus and Web of Science, until June 15, 2021. Randomized or non-randomized experimental studies that analyzed LL-RE, associated with at least two relative BFR pressures [arterial occlusion pressure (AOP)%], on myoelectric activity, fatigue, or metabolic responses were included. Random-effects meta-analyses were performed for MVC torque (fatigue measure) and myoelectric activity. The quality of evidence was assessed using the PEDro scale.Results: Ten studies were included, all of moderate to high methodological quality. For MVC torque, there were no differences in the comparisons between exercise with 40–50% vs. 80–90% AOP. When analyzing the meta-analysis data, the results indicated differences in comparisons in exercise with 15–20% 1 repetition maximum (1RM), with higher restriction pressure evoking greater MVC torque decline (4 interventions, 73 participants; MD = −5.05 Nm [95%CI = −8.09; −2.01], p = 0.001, I2 = 0%). For myoelectric activity, meta-analyses indicated a difference between exercise with 40% vs. 60% AOP (3 interventions, 38 participants; SMD = 0.47 [95%CI = 0.02; 0.93], p = 0.04, I2 = 0%), with higher pressure of restriction causing greater myoelectric activity. This result was not identified in the comparisons between 40% vs. 80% AOP. In analysis of studies that adopted pre-defined repetition schemes, differences were found (4 interventions, 52 participants; SMD = 0.58 [95%CI = 0.11; 1.05], p = 0.02, I2 = 27%).Conclusion: The BFR pressure applied during the LL-RE may affect the magnitude of muscle fatigue and excitability when loads between 15 and 20% of 1RM and predefined repetition protocols (not failure) are prescribed, respectively.Systematic Review Registration: [http://www.crd.york.ac.uk/prospero], identifier [CRD42021229345].

Hypertrophic effects of low-load blood flow restriction training with different repetition schemes: A systematic review and meta-analysis

“…Six studies [5,17,23,[31][32][33] presented the data graphically. Data from these studies were estimated using ImageJ software [34]. In six studies [10,11,14,16,18,20] the data either were not available or could not be extracted from graphs, and we therefore requested the data from the corresponding author via e-mail.…”

Blood Flow Restriction Training for Tendinopathy Rehabilitation: A Potential Alternative to Traditional Heavy-Load Resistance Training

“…Arterial occlusion pressure is the amount of pressure required to cease blood-flow within the targeted limb, which varies between individuals subject to characteristics such as body size and health status [68,69]. There are wide variances in occlusion pressures throughout studies, with many suggesting an individualised approach should be taken to account for individual characteristics, with recommended pressures typically ranging between 40-80% arterial occlusion [70][71][72][73][74][75][76][77]. The width of BFRT cuffs is another important consideration, as cuff width will affect the pressure required to achieve arterial occlusion, with variances in size between 3-18 cm common in studies [78][79][80][81].…”

Acute Effects of Blood Flow Restriction Training on Movement Velocity and Neuromuscular Signal during the Back Squat Exercise

“…However, it is also known that corticospinal excitability increases after BFRT, showing higher activation levels in comparison with traditional training [2]. These findings suggests that BFRT may lead to a better neural performance [15], which is usually monitored during training through velocity movement control [16] since it allows load quantification [17], 1-RM estimation [18], and neuromuscular fatigue monitorization [19,20].…”