Effect of Blood Flow Restriction Training on Physiological Outcomes in Healthy Athletes: a Systematic Review and Meta-Analysis

Background. Blood flow restriction (BFR) training is gaining increasing attention in the scientific community. Studies using exercise combined with blood flow restriction have shown muscle strength and size improvement. In fact, the main feature of BFR training is that can elicit muscle hypertrophy and strength adaptations using light external loads (20-30% one repetition maximum, 1RM) comparable to what is typically seen following high-load (IIL) training programs with 70-85% 1RM. This specific training has applications for individuals who may not be able to tolerate ihe mechanical stresses associated with higher loads, such as the elderly or injured; thus, several investigations have focused on implementing BFR exercise within older and clinical populations. However, the effects of this kind of technique in healthy athletes are not dear in scientific literature. The purpose of this study is to conduct a systematic review with meta-analysis to evaluate the qualitative and quantitative results of blood flow restriction training in healthy athletes.Methods. PRISMA guidelines were used to carry out the systematic review and meta-analysis. Three electronic databases were searched: MEDLINE, PEDro, and the Cochrane Library. Papers included in the study have the following characteristics: a) a randomized controlled trial or clinical trial design of research, b) studies investigating physiological effects of BFR training in healthy athletes and c) published in English. The approach to data extraction was chosen on the basis of the Cochrane Methods. Studies quality and risk of bias of the clinical trials included were evaluated according to a adad score and through meta-analysis.Results. After the elimination of duplicates, 164 records were screened. Among these, 14 studies were included in the systematic review. Seven of these were involved in the meta-analysis. From the qualitative analysis, a larger number of studies were found with a low level of quality.Conclusions. The application of BFR positively influences muscular adaptations compared with exercise under normal blood-flow conditions, in terms of increased VO2 max, higher strength increase, and muscles adaptations. Thus. BFR provides a feasible, promising, and beneficial complementary training stimuli when used in a controlled environment supervised by trained and experienced personnel.