Use and safety of KAATSU training:Results of a national survey

Effects of Blood Flow Restriction Training on the Upper Extremities: A Scoping Review

High-intensity training leads to muscle growth in the upper extremities but at the expense of a greater risk of damaging joints, ligaments, or tendons due to this region being more prone to injury. In contrast, low-intensity resistance training implements a low load with high repetition, which is safer but yields less muscle hypertrophy and greater time consumption. Blood flow restriction (BFR) training potentially provides a solution as it achieves the muscle growth and strengthening of high-intensity resistance training while safely performing low-intensity resistance training. This technique reduces venous return and arterial blood flow to the targeted limb, creating a physiological environment to induce muscle hypertrophy, increase strength, and prolong endurance while minimizing tissue stress. This study will analyze literature within the past 10 years on the usage of BFR training in the upper extremities. An extensive search on PubMed was performed using the term "blood flow restriction training upper extremity," which resulted in 98 articles that were narrowed down to 17 based on clinical trials and relevance to upper extremities. Results from this study demonstrate that BFR training enhances muscle hypertrophy and strength in the upper extremity muscles, including the biceps brachii and triceps brachii at low loads. Additionally, BFR training has been shown to promote adaptations in non-occluded muscles proximal and contralateral to the cuff location. Clinical applications include postoperative recovery, rehabilitation of rotator cuff injuries, and treatment of tendinopathies. BFR training offers an effective alternative to high-load resistance training for the upper extremities with promising applications in rehabilitation and injury prevention. Future research is necessary to address long-term effects, optimize protocols, and diversify its applications.

Vascular occlusion for optimising the functional improvement in patients with knee osteoarthritis: a randomised controlled trial

OBJECTIVES

Knee osteoarthritis (KOA) is a leading cause of global disability with conventional exercise yielding only modest improvements. Here we aimed to investigate the benefits of integrating blood flow restriction (BFR) into traditional exercise programmes to enhance treatment outcomes.

METHODS

The Vascular Occlusion for optimizing the Functional Improvement in patients with Knee Osteoarthritis randomised controlled trial enrolled 120 patients with KOA at Ghent University Hospital, randomly assigning them to either a traditional exercise programme or a BFR-enhanced programme over 24 sessions in 12 weeks. Assessments were conducted at baseline, 6 weeks, 12 weeks and 3 months postintervention using linear mixed models with Dunn-Sidak corrections for multiple comparisons. Primary outcome was the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire at 3 months follow-up with knee strength, Pain Catastrophizing Scale questionnaire and functional tests as secondary outcomes. Analysis followed an intention-to-treat approach (NCT04996680).

RESULTS

The BFR group showed greater improvements in KOOS pain subscale (effect size (ES)=0.58; p=0.0009), quadriceps strength (ES=0.81; p<0.0001) and functional tests compared with the control group at 12 weeks. At 3 months follow-up, the BFR group continued to exhibit superior improvements in KOOS pain (ES=0.55; p=0.0008), symptoms (ES=0.59; p=0.0004) and quality of life (QoL) (ES=0.66; p=0.0001) with sustained benefits in secondary outcomes. Drop-out rates were similar in both groups.

CONCLUSION

Incorporating BFR into traditional exercise programmes significantly enhances short-term and long-term outcomes for patients with KOA demonstrating persistent improvements in pain, symptoms, QoL and functional measures compared with conventional exercise alone. These findings suggest that BFR can provide the metabolic stimulus needed to achieve muscle strength and functional gains with lower mechanical loads. Reduced pain and increased strength support a more active lifestyle, potentially maintaining muscle mass, functionality and QoL even beyond the supervised intervention period.

TRIAL REGISTRATION NUMBER

NCT04996680.

How Does Blood-Flow Restriction Alter Forehand Drive Performance and Muscle Recruitment in Tennis Players?

PURPOSE

To examine the acute effects of forehand drive (FD) preconditioning with or without blood-flow restriction (BFR) on subsequent forehand performance and muscle recruitment in tennis.

METHODS

On separate visits, 12 well-trained tennis players participated in 4 randomized trials. Each visit included pretests (maximal muscle-activation capacity or FD performance), a preconditioning phase, and posttests after 5 minutes of rest (ie, similar to pretests). The preconditioning phase involved 5 sets of 10 maximal-effort FD exercises, performed either with (EXP) or without (CON) BFR (50% of the arterial occlusion pressure applied to dominant lower and upper limbs). During the pretest and posttests, either maximal voluntary isometric contraction (MVIC) with surface electromyography recordings of 6 muscles (gastrocnemius, rectus femoris, biceps brachii, anterior deltoid, external oblique, and pectoralis major) or ball velocity and accuracy of 10 crosscourt forehands were assessed.

RESULTS

Peak ball velocity increased from pretests to posttests (+2.3% [2.3%]; P = .004), regardless of the condition (P = .130). Peak ball accuracy remained unchanged (P > .05). From pretests to posttests, increases in electromyography levels for the biceps brachii muscle were larger for EXP (+14.5% [7.4%]; P < .001) than CON (+7.3% [10.3%]; P = .042). During the preconditioning phase, biceps brachii muscle activity was higher for EXP than CON (+7.4% [7.3%]; P = .006) during MVICs. Surface electromyography levels remained unchanged for other muscles.

CONCLUSION

Executing FD exercises during a preconditioning phase acutely improved FD velocity but not accuracy in tennis, also accompanied by increased recruitment of the biceps brachii muscle. However, adding BFR did not significantly enhance these benefits.

Effects of Different Blood Flow Restriction Training Modes on Body Composition and Maximal Strength of Untrained Individuals

BACKGROUND

The objective of this study was to examine the impacts of absolute cuff pressure blood flow restriction (A-BFR) training and incremental cuff pressure blood flow restriction (I-BFR) training, under equal cuff pressures, on body composition and maximal strength among untrained adults. Additionally, we aimed to compare these effects with those observed in high-load resistance training (HL-RT).

METHODS

Thirty-three adults without prior professional sports or resistance training experience were recruited and randomly assigned to three groups (n = 11 per group) for an 8-week training program, held three times weekly. The A-BFR group trained with a 20% 1RM load and a cuff occlusion pressure set at 190 mmHg. The I-BFR group initiated training with an occlusion pressure of 160 mmHg, which incrementally increased by 20 mmHg every two weeks, with other conditions mirroring those of the A-BFR group. The HL-RT group trained with a 70% 1RM load.

RESULTS

All three groups demonstrated a statistically significant improvement in lower-body maximal strength (p < 0.01), with no significant differences observed among the groups (p > 0.05). A notable increase in left-leg muscle mass was seen across all groups (p < 0.05). However, total muscle mass, right-leg muscle mass, fat-free mass, BMI, bone mineral density, and bone mineral content remained relatively unchanged (p > 0.05), with no significant differences among the groups (p > 0.05). Only the HL-RT group exhibited a significant increase in left-leg thigh circumference (p < 0.05), while right-leg thigh circumference remained stable (p > 0.05), with no significant intergroup differences (p > 0.05).

CONCLUSIONS

While A-BFR and I-BFR did not yield statistically significant differences in overall training outcomes, A-BFR demonstrated a slightly stronger potential. A-BFR and I-BFR achieved comparable gains in muscle strength and improvements in body composition to those seen with HL-RT. However, HL-RT demonstrated more significant improvements in leg circumference.

Comparison of Blood Flow Restriction Interventions to Standard Rehabilitation After an Anterior Cruciate Ligament Injury: A Systematic Review

BACKGROUND

Blood flow restriction training (BFR-t) data are heterogeneous. It is unclear whether rehabilitation with BFR-t after an anterior cruciate ligament (ACL) injury is more effective in improving muscle strength and muscle size than standard rehabilitation.

PURPOSE

To review outcomes after an ACL injury and subsequent reconstruction in studies comparing rehabilitation with and without BFR-t.

STUDY DESIGN

Systematic review. Level of evidence, 3.

METHODS

A search of English-language human clinical studies published in the past 20 years (2002-2022) was carried out in 5 health sciences databases, involving participants aged 18-65 undergoing rehabilitation for an ACL injury. Outcomes associated with muscle strength, muscle size, and knee-specific patient-reported outcome measures (PROMs) were extracted from studies meeting inclusion criteria and compared.

RESULTS

The literature search identified 279 studies, of which 5 met the selection criteria. Two studies suggested that BFR-t rehabilitation after an ACL injury improved knee or thigh muscle strength and muscle size compared with rehabilitation consisting of comparable and higher load resistance training, with two studies suggesting the opposite. The single study measuring PROMs showed improvement compared to traditional rehabilitation, with no difference in muscle strength or size.

CONCLUSION

BFR-t after an ACL injury seems to benefit muscle strength, muscle size, and PROM scores compared with standard rehabilitation alone. However, only 1 large study included all these outcomes, which has yet to be replicated in other settings. Further studies utilizing similar methods with a common set of outcome measures are required to confirm the effects of BFR-t on ACL rehabilitation.

Effects of Blood Flow Restriction Training on Muscle Strength and Hypertrophy in Untrained Males: A Systematic Review and Meta-Analysis Based on a Comparison with High-Load Resistance Training

This meta-analysis examined the efficacy of low-load resistance training with blood flow restriction (LL-BFR) versus high-load resistance training (HL-RT) on muscle strength and hypertrophy, exploring factors affecting outcomes. We searched Embase, CNKI, Wanfang, PubMed, Ovid Medline, ProQuest, Cochrane Library, Embase, and Scopus from inception to July 2024. After assessing the risk of bias using the Cochrane tool, a meta-analysis was conducted to calculate the overall effect size. Subgroup analyses were performed to explore the impact of different modulating factors on training effects. LL-BFR was found to be inferior to HL-RT with regard to muscle strength gains (SMD = -0.33, 95% CI: -0.49 to -0.18, p < 0.0001). However, subgroup analyses revealed that LL-BFR achieved muscle strength gains comparable to HL-RT under individualized pressure (SMD = -0.07, p = 0.56), intermittent cuff inflation (SMD = -0.07, p = 0.65), and a higher number of training sessions (SMD = -0.12, p = 0.30). No significant difference in muscle mass gains was observed between LL-BFR and HL-RT (SMD = 0.01, p = 0.94), and this conclusion remained consistent after controlling for modulating variables. HL-RT is superior to LL-BFR in enhancing muscle strength gains. Nevertheless, under appropriate conditions, including individualized pressure prescription, intermittent cuff inflation, and a higher number of training sessions, LL-BFR can achieve muscle strength gains comparable to HL-RT, emphasizing the importance of tailored training programs. Both methods exhibit similar effects on muscle mass gains, indicating that LL-BFR serves as an effective alternative for individuals who cannot perform HL-RT because of physical limitations or injury concerns.

The Effects of Blood Flow Restriction Aerobic Exercise on Body Composition, Muscle Strength, Blood Biomarkers, and Cardiovascular Function: A Narrative Review

Blood flow restriction exercise has emerged as a promising alternative, particularly for elderly individuals and those unable to participate in high-intensity exercise. However, existing research has predominantly focused on blood flow restriction resistance exercise. There remains a notable gap in understanding the comprehensive effects of blood flow restriction aerobic exercise (BFRAE) on body composition, lipid profiles, glycemic metabolism, and cardiovascular function. This review aims to explore the physiological effects induced by chronic BFRAE. Chronic BFRAE has been shown to decrease fat mass, increase muscle mass, and enhance muscular strength, potentially benefiting lipid profiles, glycemic metabolism, and overall function. Thus, the BFRAE offers additional benefits beyond traditional aerobic exercise effects. Notably, the BFRAE approach may be particularly suitable for individuals with low fitness levels, those prone to injury, the elderly, obese individuals, and those with metabolic disorders.

Effects of Acute Piano Performance With Blood Flow Restriction on Upper Limb Muscle and Perceptual Response in Pianists

BACKGROUND

 Long-term and prolonged piano performance does not provide essential skeletal muscle training benefits while increasing the risk of injury to the upper extremities. Unlike high-intensity exercise training, moderate blood flow restriction (BFR) training has been found to improve neuromuscular mechanisms with a variety of physical exercises (machine, elastic band, walking, electrical stimulation, and body weight).

AIM AND METHODS

 We investigated the physiological and perceptual responses related to piano performance with or without BFR based on acute responses of neuromuscular mechanisms. Student or professional pianists (n=7) performed the "Revolutionary Etude" on the piano with (Piano-BFR) and without (Piano-Ctrl) BFR. During the Piano-BFR performance, 150-180 mmHg of cuff pressure was applied around the most proximal region of both arms as a moderate BFR.

RESULTS

 Changes in upper limb girth, muscle thickness, and hand grip strength were measured before and immediately after the performance. After the performance, perceptual and other responses were recorded. Immediately after the performance, the Piano-BFR condition induced greater changes in girth (forearm and upper arm), muscle thickness (forearm), and handgrip strength than the Piano-Ctrl condition. Piano-BFR was (p<0.01) higher than Piano-Ctrl on eight questions regarding perceptual response (upper arm fatigue and difficulty playing the piano). Piano performance with BFR was revealed to increase upper extremity muscle size and fatigue in pianists after playing.

CONCLUSION

 Piano performance with BFR was revealed to increase upper extremity muscle size and fatigue in pianists after playing. The effect of BFR on neuromuscular mechanisms on piano performance was greater in the forearm than in the upper arm.

Effects of Low-Load Blood Flow Restriction Training on Rotator Cuff Strength and Hypertrophy: Case Series

Background

The rotator cuff (RC) plays a pivotal role in the performance and health of the shoulder and upper extremity. Blood flow restriction training (BFRT) is a modality to improve strength and muscle hypertrophy with even low-load training in healthy and injured individuals. There is minimal evidence examining its effect proximal to the occluded area, and particularly on the RC.

Hypothesis & Purpose

The purpose of this case series is to explore the effects of low-load BFRT on RC strength, hypertrophy, and tendon thickness in asymptomatic individuals.

Study Design

Case series.

Methods

Fourteen participants with asymptomatic, untrained shoulders were recruited to participate. They performed an eight-week low-load shoulder exercise regimen where BFR was applied to the dominant arm only during exercise. The dependent variables were maximal isometric strength of the shoulder external rotators(ER) and elevators (in the scapular plane in full can position) (FC) measured via handheld dynamometry, cross sectional area (CSA) of the supraspinatus and infraspinatus muscles, and supraspinatus tendon thickness measured via ultrasound imaging (US). Mean changes within and between arms were compared after training using paired t-tests. Cohen's d was used to determine effect sizes.

Results

All participants were able to complete the BFRT regimen without adverse effects. Mean strength and CSA increased for all variables in both arms, however this increase was only significant (p\<0.01) for FC strength bilaterally and CSA for the supraspinatus and infraspinatus on the BFRT side. The effect sizes for increased supraspinatus and infraspinatus CSA on the BFRT side were 0.40 (9.8% increase) and 0.46 (11.7% increase) respectively. There were no significant differences when comparing the mean changes of the BFRT side to the non-BFRT side for strength or muscle CSA. There were no significant changes to supraspinatus tendon thickness.

Conclusion

These results suggest variability in response of the RC musculature to low-load BFRT in asymptomatic individuals. The potential for a confounding systemic response in the study design makes determining whether low-load BFRT is more beneficial than low-load non-BFRT difficult. The hypertrophy seen on the BFRT side warrants further study.

Level of Evidence

4.

Survey of Blood Flow Restriction Training Applications in Sports Medicine and Performance Practice Across North America

Colapietro, MA, Lee, JZ, and Vairo, GL. Survey of blood flow restriction training applications in sports medicine and performance practice across North America. J Strength Cond Res 38(5): 856–863, 2024—This study profiled current clinical applications of blood flow restriction (BFR) training and observed side effects by surveying active sports medicine and performance personnel across North America. An online survey consisting of questions derived from a related position statement was distributed through professional organizations, email listservs, and social media. Personnel with experience applying or prescribing BFR training with permanent residence within the United States or Canada were eligible to participate. Variables captured included demographics (profession, practice setting), BFR equipment, treatment parameters, observed side effects, and personal perceptions regarding BFR training. An alpha level of p < 0.05 determined significance. A convenience sample included 72 clinicians with 67 being from the United States. Athletic trainers (n = 35) and physical therapists (n = 30) primarily participated. Chi-square test of independence indicated that a higher proportion of physical therapists (90.3%) report receiving formal education in BFR training compared with athletic trainers (65.7%) ( = 4.1, p = 0.043). Parameters varied between respondents for exercise prescription and occlusion settings. Respondents primarily followed position statement recommendations with individualized pressure selections for resistance (80.9%) and aerobic (84.8%) BFR modes. Side effects reported included delayed onset muscle soreness (66.2%), inability to continue because of pain (28%), and numbness (22.5%). Personal perceptions between athletic trainers and physical therapists were compared using independent t-tests. Physical therapists indicated higher confidence in safety (difference = 0.37 ± 0.32, p = 0.026), understanding recommendations (difference = 0.47 ± 0.37, p = 0.011), and theoretical principles (difference = 0.80 ± 0.53, p = 0.004). Despite variation in BFR parameters used, sports medicine personnel demonstrate compliance with position statement recommendations and report mild side effects.

Blood Flow Restriction Training for Meniscus Repair Surgery

Background

Blood flow restriction (BFR) is a training tool that involves wearing a tourniquet or occlusive device during exercise. Data support that low-load training with BFR may produce muscle hypertrophy similar to standard high-load training. Because of the weight-bearing and range of motion (ROM) restrictions after meniscal repair, patients encounter substantial atrophy of lower extremity musculature. We perform BFR for these patients to limit atrophy postoperatively with the goal of facilitating their return to prior function and sports.

Indications

We incorporate BFR in the postoperative rehabilitation protocol for patients undergoing meniscal repair not involving the root. Patients with the following are excluded: acute or severe cardiac disease, peripheral vascular disease, blood pressure over systolic 180 mm Hg or diastolic 100 mm Hg, hemophilia, thrombophlebitis or history of deep vein thrombosis, severe anemia, and sickle cell disease.

Technique Description

An automated BFR device calculates the patient's limb occlusion pressure (LOP) and titrates to 50% to 80% of LOP for lower extremity exercises. Exercise parameters typically consist of 4 sets of each exercise, totaling 75 repetitions, with 30-second interset rest. Patients undergo a standard 3-phase postoperative rehabilitation protocol. Phase I (weeks 0-6): Patients are nonweightbearing, may be either footflat weightbearing or partial weightbearing at the surgeon's, with ROM restricted 0 to 90 in a hinge knee brace throughout the phase. Exercises include quadriceps sets with neuromuscular electrical stimulation and straight leg raises and short/long arcs quadriceps. Phase II (weeks 7-8): Patients progress to weightbearing and ROM as tolerated and begin exercises including double mini squats, hamstring curls, double leg press, and double leg heel raises. Phase III: (weeks 9+): Patients perform double and single leg bridges, double leg bridges on ball with knee band, squats, single leg press, and single leg heel raises, all with the goal of returning to sports.

Results

Prior systematic review data demonstrate low-load training with BFR increases muscle strength and induces hypertrophy relative to low-load training alone. No significant differences for Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales between BFR training group and control group.

Discussion

BFR training may facilitate postoperative recovery in patients undergoing meniscal repair surgery by helping mitigate muscular atrophy.

Patient Consent Disclosure Statement

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Current Implementation and Barriers to Using Blood Flow Restriction Training: Insights From a Survey of Allied Health Practitioners

ABSTRACT

Scott, BR, Marston, KJ, Owens, J, Rolnick, N, and Patterson, SD. Current implementation and barriers to using blood flow restriction training: Insights from a survey of allied health practitioners. J Strength Cond Res 38(3): 481-490, 2024-This study investigated the use of blood flow restriction (BFR) exercise by practitioners working specifically with clinical or older populations, and the barriers preventing some practitioners from prescribing BFR. An online survey was disseminated globally to allied health practitioners, with data from 397 responders included in analyses. Responders who had prescribed BFR exercise ( n = 308) completed questions about how they implement this technique. Those who had not prescribed BFR exercise ( n = 89) provided information on barriers to using this technique, and a subset of these responders ( n = 22) completed a follow-up survey to investigate how these barriers could be alleviated. Most practitioners prescribe BFR exercise for musculoskeletal rehabilitation clients (91.6%), with the BFR cuff pressure typically relative to arterial occlusion pressure (81.1%) and implemented with resistance (96.8%) or aerobic exercise (42.9%). Most practitioners screen for contraindications (68.2%), although minor side effects, including muscle soreness (65.8%), are common. The main barriers preventing some practitioners from using BFR are lack of equipment (60.2%), insufficient education (55.7%), and safety concerns (31.8%). Suggestions to alleviate these barriers included developing educational resources about the safe application and benefits of BFR exercise ( n = 20) that are affordable ( n = 3) and convenient ( n = 4). These results indicate that BFR prescription for clinical and older cohorts mainly conforms with current guidelines, which is important considering the potentially increased risk for adverse events in these cohorts. However, barriers still prevent broader utility of BFR training, although some may be alleviated through well-developed educational offerings to train practitioners in using BFR exercise.

Idiosyncratic bone responses to blood flow restriction exercise: new insights and future directions

Applying blood flow restriction (BFR) during low-load exercise induces beneficial adaptations of the myotendinous and neuromuscular systems. Despite the low mechanical tension, BFR exercise facilitates a localized hypoxic environment and increase in metabolic stress, widely regarded as the primary stimulus for tissue adaptations. First evidence indicates that low-load BFR exercise is effective in promoting an osteogenic response in bone, although this has previously been postulated to adapt primarily during high-impact weight-bearing exercise. Besides studies investigating the acute response of bone biomarkers following BFR exercise, first long-term trials demonstrate beneficial adaptations in bone in both healthy and clinical populations. Despite the increasing number of studies, the physiological mechanisms are largely unknown. Moreover, heterogeneity in methodological approaches such as biomarkers of bone metabolism measured, participant and study characteristics, and time course of measurement renders it difficult to formulate accurate conclusions. Furthermore, incongruity in the methods of BFR application (e.g., cuff pressure) limits the comparability of datasets and thus hinders generalizability of study findings. Appropriate use of biomarkers, effective BFR application, and befitting study design have the potential to progress knowledge on the acute and chronic response of bone to BFR exercise and contribute toward the development of a novel strategy to protect or enhance bone health. Therefore, the purpose of the present synthesis review is to 1) evaluate current mechanistic evidence; 2) discuss and offer explanations for similar and contrasting data findings; and 3) create a methodological framework for future mechanistic and applied research.

Feasibility of Low-Load Resistance Training Using Blood Flow Restriction for People With Advanced Multiple Sclerosis: A Prospective Cohort Study

OBJECTIVE

The objective of this study was to determine the feasibility of low-load resistance training with blood flow restriction (BFR) for people with advanced disability due to multiple sclerosis (MS).

METHODS

In this prospective cohort study, 14 participants with MS (Expanded Disability Status Scale [EDSS] score = 6.0 to 7.0; mean age = 55.4 [SD = 6.2] years; 71% women) were asked to perform 3 lower extremity resistance exercises (leg press, calf press, and hip abduction) bilaterally twice weekly for 8 weeks using BFR. Feasibility criteria were as follows: enrollment of 20 participants, ≥80% retention and adherence, ≥90% satisfaction, and no serious adverse events related to the intervention. Other outcomes included knee extensor, ankle plantar flexor, and hip abductor muscle strength, 30-Second Sit-to-Stand Test, Berg Balance Scale, Timed 25-Foot Walk Test, 12-Item MS Walking Scale, Modified Fatigue Impact Scale, Patient-Specific Functional Scale, and daily step count.

RESULTS

Sixteen participants consented, and 14 completed the intervention, with 93% adherence overall. All participants were satisfied with the intervention. A minor hip muscle strain was the only intervention-related adverse event. There were muscle strength improvements on the more-involved (16%-28%) and less-involved (12%-19%) sides. There were also changes in the 30-Second Sit-to-Stand Test (1.9 repetitions; 95% CI = 1.0 to 2.8), Berg Balance Scale (5.3 points; 95% CI = 3.2 to 7.4), Timed 25-Foot Walk Test (-3.3 seconds; 95% CI = -7.9 to 1.3), Modified Fatigue Impact Scale (-8.8 points; 95% CI = -16.5 to -1.1), 12-Item MS Walking Scale (-3.6 points; 95% CI = -11.5 to 4.4), Patient-Specific Functional Scale (2.9 points; 95% CI = 1.9 to 3.8), and daily step count (333 steps; 95% CI = -191 to 857).

CONCLUSION

Low-load resistance training using BFR in people with MS and EDSS scores of 6.0 to 7.0 appears feasible, and subsequent investigation into its efficacy is warranted.

IMPACT

Although efficacy data are needed, combining BFR with low-load resistance training may be a viable alternative for people who have MS and who do not tolerate conventional moderate- to high-intensity training because of more severe symptoms, such as fatigue and weakness.

LAY SUMMARY

Low-load strength training with BFR was feasible in people who have advanced disability due to MS. Using BFR may provide an alternative for people with MS who do not tolerate higher intensity training due to more severe symptoms, such as fatigue and weakness.

Comparing the efficacy of low-load resistance exercise combined with blood flow restriction versus conventional-load resistance exercise in Chinese community-dwelling older people with sarcopenic obesity: a study protocol for a randomised controlled trial

INTRODUCTION

Sarcopenic obesity (SO) is characterised by decreased muscle mass, diminished muscle strength and/or reduced physical performance and a high percentage of body fat (PBF). Conventional-load resistance exercise (CRE) may be difficult for older people with SO owing to their declining physical functions. Low-load resistance exercise (LRE) combined with blood flow restriction (BFR; LRE-BFR) is a viable alternative to CRE for improving muscle mass and strength and potential exercise mode for managing SO. This study has two objectives: (1) to comprehensively evaluate the efficacy of CRE and LRE-BFR in improving body composition, muscle strength, physical performance, haematological parameters, cardiovascular disease (CVD) risk factors and quality of life and (2) to compare the efficacy of CRE and LRE-BFR and explore their potential mechanisms.

METHODS AND ANALYSIS

This work is a 12-week assessor-blinded randomised clinical trial that will be conducted thrice a week. Sarcopenia will be defined using the Asian Working Group for Sarcopenia 2019, and obesity will be determined using the criteria developed by the World Health Organization. Community-dwelling older people aged ≥ 65 years will be screened as the participants using inclusion and exclusion criteria. A total of 33 participants will be randomised into a CRE group (n = 11), an LRE-BFR group (n = 11) and a control group that will be given only health education (n = 11). The primary outcomes will be knee extensor strength and PBF, and the secondary outcomes will be body composition, anthropometric measurements, muscle strength of upper limbs, physical performance, haematological parameters, CVD risk factors and quality of life. The outcomes will be measured at the baseline (week 0), end of the intervention (week 12) and follow up (week 24). All the collected data will be analysed following the intention-to-treat principle.

ETHICS AND DISSEMINATION

The Ethics Research Committee has approved this study (approval No. CMEC-2022-KT-51). Changes or developments in this study will be reported at www.chictr.org.cn .

TRIAL REGISTRATION

ChiCTR2300067296 (3 January 2023).

Early- and Late-Stage Benefits of Blood Flow Restriction Training on Knee Strength in Adolescents After Anterior Cruciate Ligament Reconstruction

Background

Blood flow restriction training (BFRT) after anterior cruciate ligament reconstruction (ACLR) is rising in popularity because of its benefits in reducing muscle atrophy and mitigating knee strength deficits.

Purpose

To investigate the impact BFRT has on adolescent knee strength after ACLR at 2 postoperative time points: at 3 months and the time of return to sport (RTS).

Study Design

Cohort study; Level of evidence, 3.

Methods

A prospective intervention (BFRT) group was compared to an age-, sex-, and body mass index-matched retrospective control group. Patients aged 12 to 18 years who underwent primary ACLR with a quadriceps tendon autograft were included. Along with a traditional rehabilitation protocol, the BFRT group completed a standardized BFRT protocol (3 BFRT exercises performed twice weekly for the initial 12 weeks postoperatively). Peak torque values for isometric knee extension and flexion strength (at 3 months and RTS) and isokinetic strength at 180 deg/s (at RTS) as well as Pediatric International Knee Documentation Committee (Pedi-IKDC) scores were collected. Differences between the BFRT and control groups were compared with 2-way mixed analysis of variance and 1-way analysis of variance.

Results

The BFRT group consisted of 16 patients (10 female; mean age, 14.84 ± 1.6 years) who were matched to 16 patients in the control group (10 female; mean age, 15.35 ± 1.3 years). Regardless of the time point, the BFRT group demonstrated significantly higher isometric knee extension torque compared to the control group (2.15 ± 0.12 N·m/kg [95% CI, 1.90-2.39] vs 1.74 ± 0.12 N·m/kg [95% CI, 1.49-1.98], respectively; mean difference, 0.403 N·m/kg; P = .024). The BFRT group also reported significantly better Pedi-IKDC scores compared to the control group at both 3 months (68.91 ± 9.68 vs 66.39 ± 12.18, respectively) and RTS (89.42 ± 7.94 vs 72.79 ± 22.81, respectively) (P = .047).

Conclusion

In adolescents, the addition of a standardized BFRT protocol to a traditional rehabilitation protocol after ACLR significantly improved knee strength and patient-reported function compared to a traditional rehabilitation program alone.

Update on Current Concepts of Blood Flow Restriction in the Perioperative Period of Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament tears or ruptures are common orthopedic injuries. Anterior cruciate ligament reconstruction (ACLR) is an orthopedic procedure allowing for earlier return to sports, improved maintenance of lifestyle demands, and restored knee stability and kinematics. A perioperative rehabilitative adjunct recently gaining interest is blood flow restriction (BFR), a method in which temporary restriction of blood flow to a chosen extremity is introduced and can be used as early as a few days postoperative. There has been increasing investigation and recent literature regarding BFR. This review synthesizes current concepts of BFR use in the ACLR perioperative period. [Orthopedics. 2023;46(6):e333-e340.].

Where Does Blood Flow Restriction Fit in the Toolbox of Athletic Development? A Narrative Review of the Proposed Mechanisms and Potential Applications

Blood flow-restricted exercise is currently used as a low-intensity time-efficient approach to reap many of the benefits of typical high-intensity training. Evidence continues to lend support to the notion that even highly trained individuals, such as athletes, still benefit from this mode of training. Both resistance and endurance exercise may be combined with blood flow restriction to provide a spectrum of adaptations in skeletal muscle, spanning from myofibrillar to mitochondrial adjustments. Such diverse adaptations would benefit both muscular strength and endurance qualities concurrently, which are demanded in athletic performance, most notably in team sports. Moreover, recent work indicates that when traditional high-load resistance training is supplemented with low-load, blood flow-restricted exercise, either in the same session or as a separate training block in a periodised programme, a synergistic and complementary effect on training adaptations may occur. Transient reductions in mechanical loading of tissues afforded by low-load, blood flow-restricted exercise may also serve a purpose during de-loading, tapering or rehabilitation of musculoskeletal injury. This narrative review aims to expand on the current scientific and practical understanding of how blood flow restriction methods may be applied by coaches and practitioners to enhance current athletic development models.

Muscle strength adaptation between high-load resistance training versus low-load blood flow restriction training with different cuff pressure characteristics: a systematic review and meta-analysis

Purpose: In this systematic review and meta-analysis, blood flow restriction (BFR) with low-load resistance training (BFR-RT) was compared with high-load resistance training (HL-RT) on muscle strength in healthy adults. The characteristics of cuff pressure suitable for muscle strength gain were also investigated by analyzing the effects of applying different occlusion pressure prescriptions and cuff inflation patterns on muscle strength gain. Methods: Literature search was conducted using PubMed, Ovid Medline, ProQuest, Cochrane Library, Embase, and Scopus databases to identify literature published until May 2023. Studies reporting the effects of BFR-RT interventions on muscle strength gain were compared with those of HL-RT. The risk of bias in the included trials was assessed using the Cochrane tool, followed by a meta-analysis to calculate the combined effect. Subgroup analysis was performed to explore the beneficial variables. Results: Nineteen articles (42 outcomes), with a total of 458 healthy adults, were included in the meta-analysis. The combined effect showed higher muscle strength gain with HL-RT than with BFR-RT (p = 0.03, SMD = -0.16, 95% CI: -0.30 to -0.01). The results of the subgroup analysis showed that the BFR-RT applied with incremental and individualized pressure achieved muscle strength gain similar to the HL-RT (p = 0.8, SMD = -0.05, 95% CI: -0.44 to 0.34; p = 0.68, SMD = -0.04, 95% CI: -0.23 to 0.15), but muscle strength gain obtained via BFR-RT applied with absolute pressure was lower than that of HL-RT (p < 0.05, SMD = -0.45, 95% CI: -0.71 to -0.19). Furthermore, muscle strength gain obtained by BFR-RT applied with intermittent pressure was similar to that obtained by HL-RT (p = 0.88, SMD = -0.02, 95% CI: -0.27 to 0.23), but muscle strength gain for BFR-RT applied with continuous pressure showed a less prominent increase than that for HL-RT (p < 0.05, SMD = -0.3, 95% CI: -0.48 to -0.11). Conclusion: In general, HL-RT produces superior muscle strength gains than BFR-RT. However, the application of individualized, incremental, and intermittent pressure exercise protocols in BFR-RT elicits comparable muscle strength gains to HL-RT. Our findings indicate that cuff pressure characteristics play a significant role in establishing a BFR-RT intervention program for enhancing muscle strength in healthy adults. Clinical Trial Registration: https://www.crd.york.ac.uk/PROSPERO/#recordDetails; Identifier: PROSPERO (CRD42022364934).

Blood Flow Restriction in Oncological Patients: Advantages and Safety Considerations

BACKGROUND

Cancer, being a highly widespread disease on a global scale, has prompted researchers to explore innovative treatment approaches. In this regard, blood flow restriction has emerged as a promising procedure utilized in diverse clinical populations with favorable results including improvements in muscle strength, cardiovascular function, and postoperative recovery. The aim of this systematic review was to assess the efficacy of blood flow restriction in cancer survivors.

METHODS

An investigation was carried out using various databases until February 2023: PubMed, Scientific Electronic Library Online, Physiotherapy Evidence Database, Scopus, Web of Science, Cochrane Plus, SPORTDiscus, Physiotherapy and Podiatry of the Complutense University of Madrid, ScienceDirect, ProQuest, Research Library, Cumulative Index of Nursing and Allied Literature Complete Journal Storage, and the gray literature. To assess the methodological quality of the studies, the PEDro scale was utilized, and the Cochrane Collaboration tool was employed to evaluate the risk of bias.

RESULTS

Five articles found that blood flow restriction was beneficial in improving several factors, including quality of life, physical function, strength, and lean mass, and in reducing postoperative complications and the length of hospital stay.

CONCLUSION

Blood flow restriction can be a viable and effective treatment option. It is important to note that the caution with which one should interpret these results is due to the restricted quantity of articles and significant variation, and future research should concentrate on tailoring the application to individual patients, optimizing load progression, ensuring long-term follow-up, and enhancing the methodological rigor of studies, such as implementing sample blinding.

The feasibility, safety, and efficacy of lower limb garment-integrated blood flow restriction training in healthy adults

OBJECTIVES

Explore the feasibility of lower-limb garment-integrated BFR-training.

DESIGN

Observational study.

SETTING

Human performance laboratory.

PARTICIPANTS

Healthy males with no experience of BFR-training.

MAIN OUTCOME MEASURES

Feasibility was determined by a priori thresholds for recruitment, adherence, and data collection. Safety was determined by measuring BFR torniquet pressure and the incidence of side effects. Efficacy was determined by measuring body anthropometry and knee isokinetic dynamometry. Feasibility and safety outcomes were reported descriptively or as a proportion with 95% confidence intervals (95% CI), with mean change, 95% CIs, and effect sizes for efficacy outcomes.

RESULTS

Twelve participants (mean age 24.8 years [6.5]) were successfully recruited; 11 completed the study. 134/136 sessions were completed (adherence = 98.5%) and 100% of data were collected. There was one event of excessive pain during exercise (0.7%, 95% CI 0.0%, 4.0%), two events of excessive pain post-exercise (1.5%, 95% CI 0.4%, 5.5%), and one event of persistent paraesthesia post-exercise (0.7%, 95% CI 0.0%, 4.0%). Mean maximal BFR torniquet pressure was <200 mmHg. We observed an increase in knee extension peak torque (mean change 12.4 Nm), but no notable changes in body anthropometry.

CONCLUSIONS

Lower-limb garment-integrated BFR-training is feasible, has no signal of important harm, and could be used independently.

Effect on muscle strength after blood flow restriction resistance exercise in early in-patient rehabilitation of post-chronic obstructive pulmonary disease acute exacerbation, a single blinded, randomized controlled study

BACKGROUND

Early commencement of rehabilitation might counteract the loss of muscle strength due to a chronic obstructive pulmonary disease acute exacerbation (COPDAE). Blood flow restriction resistance exercise (BFR-RE) using a low intensity of training load has demonstrated muscle strength gain in varieties of clinical populations. This trial aimed at studying the efficacy and acceptability of BFR-RE in patients with post-COPDAE which was not reported before.

METHOD

A prospective, assessor blinded, randomized controlled study with 2-week in-patient rehabilitation program with BFR-RE was compared to a matched program with resistance exercise without BFR in patients with post-COPDAE. The primary outcome was the change of muscle strength of knee extensor of dominant leg. The secondary outcomes included changes of hand grip strength (HGS), 6-minute walk test (6MWT) distance, short physical performance battery (SPPB) scores, COPD assessment test (CAT) scores; acceptability and feasibility of BFR-RE; and 1-month unplanned re-admission rate.

RESULTS

Forty-Five post-COPDAE patients (mean age = 76 ± 10, mean FEV1%=49% ± 24%) were analyzed. After training, BFR-RE group and control group demonstrated a statistically significant median muscle strength gain of 20 (Interquartile range (IQR) 3 to 38) Newton(N) and 12 (IQR -9 to 30) N respectively. BFR-RE group showed a significant change in SPPB scores, but not in 6MWT distance and HGS after training. Between groups did not have statistically significant different in all primary and secondary outcomes, though with similar acceptability. Drop-out rate due to training-related discomfort in BFR-RE group was 3.7%.

CONCLUSION

BFR-RE is feasible and acceptable in patients with post-COPDAE. A 2-week inpatient pulmonary rehabilitation with BFR-RE improved muscle strength of knee extensors, but not a greater extent than the same rehabilitation program with resistance exercise without BFR. Further studies could be considered with a longer training duration and progression of resistance load. [ClinicalTrials.gov Identifier: NCT04448236].

Blood Flow Restriction Following ACL Reconstruction

Background

Blood flow restriction (BFR) therapy is a technique that uses partial occlusion of arterial blood flow in tandem with low-load resistance training to promote an environment of metabolic stress within muscle tissue. It is hypothesized that such therapy can facilitate protein synthesis and muscle hypertrophy even in the setting of age, injury, or postoperative rehabilitation-conditions which are marred by muscle atrophy and progressive loss of function. Therefore, BFR may be a successful option to facilitate strength gains even in patients unable to perform traditional high-load resistance training.

Indications

BFR therapy has been shown to be efficacious when used in healthy athletes, the elderly, or in postoperative patients undergoing rehabilitation after upper or lower extremity procedures. More specifically, BFR application in patients undergoing knee surgery has been shown to reduce muscle atrophy post operatively.

Technique Description

BFR involves application of a tourniquet or occlusion cuff at 70% of the determined arterial occlusion pressure (commonly 150-180 mm Hg). The arterial occlusion pressure is calculated by observing the loss of Doppler ultrasonography signal at the pedal pulses with sequential inflation of a blood pressure cuff. This cuff should be applied as proximal as possible at the affected extremity. The patient subsequently performs 5 exercises, including 3 sets of 15 repetitions of each exercise, with 30 seconds of rest in between sets. The cuff remains inflated for all 5 exercises.

Results

BFR in tandem with low-load resistance training has been shown to be effective in improving lower extremity muscle torque and mass of the quadriceps and hamstring muscles when used after knee surgery, specifically anterior cruciate ligament (ACL) reconstruction. The most commonly reported adverse outcomes after BFR include muscle soreness and sensory paresthesias; however, BFR is generally believed to be safe and acceptable for use in a broad spectrum of patients.

Discussion/Conclusion

Muscle atrophy and loss of strength are hallmarks of aging, injured, and postoperative patients. Traditional means of high-intensity strength training is not feasible in these patient populations, and the use of BFR in tandem with lower intensity strength training shows promise in its ability to promote improvements in muscle strength and hypertrophy. However, more high-level research into the long-term effects, complications, and optimal BFR training regimen is warranted.

Patient Consent Disclosure Statement

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Comparative Perceptual, Affective, and Cardiovascular Responses between Resistance Exercise with and without Blood Flow Restriction in Older Adults

Older adults and patients with chronic disease presenting with muscle weakness or musculoskeletal disorders may benefit from low-load resistance exercise (LLRE) with blood flow restriction (BFR). LLRE-BFR has been shown to increase muscle size, strength, and endurance comparable to traditional resistance exercise but without the use of heavy loads. However, potential negative effects from LLRE-BFR present as a barrier to participation and limit its wider use. This study examined the perceptual, affective, and cardiovascular responses to a bout of LLRE-BFR and compared the responses to LLRE and moderate-load resistance exercise (MLRE). Twenty older adults (64.3 ± 4.2 years) performed LLRE-BFR, LLRE and MLRE consisting of 4 sets of leg press and knee extension, in a randomised crossover design. LLRE-BFR was more demanding than LLRE and MLRE through increased pain (p ≤ 0.024, d = 0.8-1.4) and reduced affect (p ≤ 0.048, d = -0.5--0.9). Despite this, LLRE-BFR was enjoyed and promoted a positive affective response (p ≤ 0.035, d = 0.5-0.9) following exercise comparable to MLRE. This study supports the use of LLRE-BFR for older adults and encourages future research to examine the safety, acceptability, and efficacy of LLRE-BFR in patients with chronic disease.

Effects of Blood Flow Restriction Therapy for Muscular Strength, Hypertrophy, and Endurance in Healthy and Special Populations: A Systematic Review and Meta-Analysis

OBJECTIVES

Blood flow restriction (BFR) training is an increasingly applied tool with potential benefits in muscular hypertrophy, strength, and endurance. This study investigates the effectiveness of BFR training relative to other forms of training on muscle strength, hypertrophy, and endurance.

DATA SOURCES

We performed systematic searches of MEDLINE, Embase, and PubMed and assessed the methodological quality of included studies using the Cochrane risk of bias tool.

MAIN RESULTS

We included 53 randomized controlled trials with 31 included in meta-analyses. For muscular strength comparing low-intensity BFR (LI-BFR) training with high-intensity resistance training (HIRT), the pooled mean difference (MD) for 1 repetition maximum was 5.34 kg (95% CI, 2.58-8.09; P < 0.01) favoring HIRT. When comparing LI-BFR training with HIRT for torque, the MD was 6.35 N·m (95% CI, 0.5-12.3; P = 0.04) also favoring HIRT. However, comparing LI-BFR with low-intensity resistance training (LIRT) for torque, there was a MD of 9.94 N·m (95% CI, 5.43-14.45; P < 0.01) favoring BFR training. Assessing muscle hypertrophy, the MD in cross-sectional area was 0.96 cm2 (95% CI, 0.21-1.7; P = 0.01) favoring pooled BFR training compared with nonocclusive training. Assessing endurance, V̇o2 maximum demonstrated a greater mean increase of 0.37 mL/kg/min (95% CI, -0.97 to 3.17; P = 0.64) in BFR endurance training compared with endurance training alone.

CONCLUSION

Blood flow restriction training produced increases in muscular strength, hypertrophy, and endurance. Comparing LI-BFR training with HIRT, HIRT was a significantly better training modality for increasing muscle hypertrophy and strength. However, LI-BFR was superior when compared with a similar low-intensity protocol. Blood flow restriction training is potentially beneficial to those unable to tolerate the high loads of HIRT; however, better understanding of its risk to benefit ratio is needed before clinical application.

LEVEL OF EVIDENCE

Level 1.

Resistance Training with Blood Flow Restriction and Ocular Health: A Brief Review

Despite the many health benefits of resistance training, it has been suggested that high-intensity resistance exercise is associated with acute increases in intraocular pressure which is a significant risk factor for the development of glaucomatous optic nerve damage. Therefore, resistance training using a variety of forms (e.g., resistance bands, free weights, weight machines, and bodyweight) may be harmful to patients with or at risk of glaucoma. An appropriate solution for such people may involve the combination of resistance training and blood flow restriction (BFR). During the last decade, the BFR (a.k.a. occlusion or KAATSU training) method has drawn great interest among health and sports professionals because of the possibility for individuals to improve various areas of fitness and performance at lower exercise intensities. In comparison to studies evaluating the efficiency of BFR in terms of physical performance and body composition changes, there is still a paucity of empirical studies concerning safety, especially regarding ocular health. Although the use of BFR during resistance training seems feasible for glaucoma patients or those at risk of glaucoma, some issues must be investigated and resolved. Therefore, this review provides an overview of the available scientific data describing the influence of resistance training combined with BFR on ocular physiology and points to further directions of research.

Blood-flow restricted exercise following ankle fractures - A feasibility study

BACKGROUND

The objective was to investigate the feasibility of blood flow restricted exercise (BFRE) as a rehabilitation modality in patients with a unilateral ankle fracture.

METHODS

Feasibility study with a prospective cohort design. Inclusion criteria were above 18 years of age and unilateral ankle fractures.

EXCLUSION CRITERIA

history of cardiac or embolic diseases, cancer, diabetes, hypertension and family history of cardio or vascular diseases. The predefined feasibility outcome was based on three criteria regarding patients experience with participating in the BFRE protocol and the absence of any serious adverse events.

RESULTS

Eight patients were included. Median age was 33 years (range: 23-60). All eight patients reported maximum satisfaction on the two questions regarding patient's perception of the overall experience with BFRE training and the feasibility to introduce BFRE as an intervention.

CONCLUSION

Early use of BFRE in patients with unilateral ankle fractures seems feasible in patients without comorbidity.

Differences in the limb blood flow between two types of blood flow restriction cuffs: A pilot study

Introduction: The determination of the optimal occlusion level is a key parameter in blood flow restriction (BFR). This study aimed to compare the effects of elastic (BStrong) vs. nylon (Hokanson) BFR cuffs on blood flow in the lower and upper limbs.

Methods: Eleven healthy participants undertook several BFR sessions with 2 different cuffs of similar width on their lower and upper limbs at different pressures [200, 250, 300, 350, and 400 mmHg for BStrong and 0, 40, and 60% of the arterial occlusion pressure (AOP) for Hokanson]. Doppler ultrasound recorded blood flows through the brachial and femoral artery at rest.

Results: With BStrong, only 350 and 400 mmHg pressures were significantly different from resting values (0% AOP). With Hokanson, both 40% and 60% of the AOP were significantly different from resting values (p < 0.05).

Discussion: While both cuffs elicited BFR, they failed to accurately modulate blood flow. Hokanson is appropriate for research settings while BStrong appears to be a convenient tool for practitioners due to its safety (i.e., the impossibility of completely occluding arteries) and the possibility of exercising freely detached from the pump.

Current Trends in Blood Flow Restriction

Purpose: The purpose of the study was to explore how individuals in the United States of America applied BFR/KAATSU devices and administered BFR/KAATSU training. In addition, the study sought to examine safety topics related to BFR/KAATSU training. Methods: The study was completed using survey research. Subjects were recruited through Facebook, email, and word of mouth. The survey was developed, piloted, and finally deployed March 22, 2021-April 21, 2021. Results: In total, 148 consented to the research; 108 completed the survey, and of those 108, 70 indicated current use with BFR/KAATSU equipment. Professions represented included athletic training, personal training, physical therapy, and strength and conditioning. Among those currently using BFR/KAATSU training (n = 70), the following results were found. The most common devices used were inflatable devices (n = 43, 61.4%). Education completed prior to device administration was formal (n = 39, 55.7%) and/or self-directed (n = 37, 52.9%). Barriers were faced by 29 (41.4%) when trying to enact training. Techniques and parameters varied during application. Screening processes were used (n = 50, 71.4%) prior to training. The devices were used to determine restrictive pressure (n = 31, 44.3%), and a supine position was used most when determining initial restrictive pressure (n = 33, 47.1%). For subsequent restrictive pressure measurements, respondents repeated the same method used initially (n = 38, 54.3%). Workload was often defined as the length of time under tension/load (n = 22, 31.4%) and exercise was directly supervised (n = 52, 74.3%). Adverse effects included bruising, lightheadedness, and cramping (n = 15, 21.4%). The devices have also been applied on those with pathology (n = 16, 22.9%). Conclusion: Those using blood flow restriction/KAATSU devices came from several professions and used an assortment of devices for BFR/KAATSU training. Individuals applied devices using a variety of parameters on populations for which efficacy has and has not been well defined.

Effects of blood flow restriction (BFR) with resistance exercise on musculoskeletal health in older adults: a narrative review

Background

Aging leads to a number of structural and physiological deficits such as loss of muscle mass and strength. Strength training at ~ 70% of 1 repetition max (RM) is recommended to prevent age-related loss of muscle mass and strength. However, most older adults may not be able to perform 70% of 1RM or higher intensity. An alternative exercise training program combining low intensity resistance exercise with blood flow restriction (BFR) can result in similar acute and chronic benefits to skeletal muscles in older adults.

Main body and short conclusion

The potential mechanisms involved are discussed, and include reactive hyperaemia, metabolic stress, and hypoxia. Key issues and safety with the use of BFR in older adults, especially those with chronic conditions are also discussed. Although there has been no reported evidence to suggest that BFR elevates the risk of clinical complications any more than high intensity exercise, it is recommended for individuals to be medically cleared of any cardiovascular risks, prior to engaging in BFR exercise.

Selected Methods of Resistance Training for Prevention and Treatment of Sarcopenia

Resistance training is an extremely beneficial intervention to prevent and treat sarcopenia. In general, traditional high-load resistance training improves skeletal muscle morphology and strength, but this method is impractical and may even reduce arterial compliance by about 20% in aged adults. Thus, the progression of resistance training methods for improving the strength and morphology of muscles without applying a high load is essential. Over the past two decades, various resistance training methods that can improve skeletal muscle mass and muscle function without using high loads have attracted attention, and their training effects, molecular mechanisms, and safety have been reported. The present study focuses on the relationship between exercise load/intensity, training effects, and physiological mechanisms as well as the safety of various types of resistance training that have attracted attention as a measure against sarcopenia. At present, there is much research evidence that blood-flow-restricted low-load resistance training (20–30% of one repetition maximum (1RM)) has been reported as a sarcopenia countermeasure in older adults. Therefore, this training method may be particularly effective in preventing sarcopenia.

An Overview of Blood Flow Restriction Physiology and Clinical Considerations

ABSTRACT

The utilization of blood flow restriction has garnished considerable attention due to its widespread application and benefits that include strength enhancement, muscle hypertrophy, and increased level of function for specific populations. Blood flow restriction induces a hypoxic environment within a muscle group, initiating a metabolic cascade that stimulates muscle protein synthesis, altered gene regulation of muscle satellite cells, and increased muscle fiber recruitment, ultimately resulting in improved strength and endurance. When using blood flow restriction, consideration of the individual patient, occlusion pressure, cuff width, and cuff size are paramount. Blood flow restriction has been proven to be a consistently safe and effective tool for augmenting rehabilitative regimens for the upper and lower extremity.

Clinical use of blood flow restriction in people with neurologic conditions: a cross-sectional survey

[Purpose] There is little evidence for blood flow restriction (BFR), or Kaatsu, training in people with neurologic conditions. This study's purpose was to survey clinicians on BFR use in people with neurologic conditions. [Participants and Methods] One-hundred twelve physical therapists and other healthcare professionals who reported using BFR in the past 5 years completed an anonymous, online survey. [Results] Eighty-nine percent of respondents thought BFR was safe in people with neurologic conditions. Meanwhile, 38% reported BFR use in people with neurologic conditions. The most common intervention used with BFR was resistance training (n=33) and the most commonly reported benefit was improved strength (n=27). The most common side-effect causing treatment to stop was intolerance to pressure (n=6). No side-effects requiring medical attention were reported. In order to support future BFR use in neurologic populations, the most common response was the need for more research (n=63). [Conclusion] Despite the lack of evidence, clinical use of BFR in people with neurologic conditions may be somewhat common. Although this study had a relatively small sample size and collected data retrospectively, the results support the potential clinical feasibility and safety of BFR use in patients with neurologic conditions and suggest that more research is needed.

Overall Safety and Risks Associated with Blood Flow Restriction Therapy: A Literature Review

INTRODUCTION

Blood flow restriction therapy (BFRT) is used in scenarios ranging from muscle building in athletic performance to decreasing recovery time in postoperative orthopedic rehabilitation. The efficacy of BFRT for treating diseases has been increasingly researched; however, there has been less literature focused on establishing the safety of this therapy.

MATERIALS AND METHODS

An extensive literature review pertaining to BFRT and any deleterious events related to its usage was completed by searching multiple databases, including PubMed, EMBASE, and Cochrane Library using the terms "blood flow restriction therapy" or "KAATSU."

RESULTS

Ten case reports, five case series, two national surveys, two questionnaires, six randomized controlled studies, and one systematic review were included. A total of 1,672 individuals reported an adverse event following BFRT use out of 25,813 individuals. Commonly reported adverse events were numbness, dizziness, subcutaneous hemorrhage, and rhabdomyolysis. There were unique adverse effects of this therapy reported in individuals with comorbid conditions, such as hypertension and thoracic outlet syndrome, which included isolated cases of central retinal vein occlusion and Paget-Schroeder syndrome.

CONCLUSION

Blood flow restriction provides tremendous opportunity with a potential for accelerated exercise rehabilitation and injury prevention. This modality could be used in the military setting to help injured active duty personnel expeditiously return to deployable status. Further prospective randomized controlled trials are warranted to further support BFRT safety; however, from this literature review, it can be concluded that BFRT can be utilized safely in the proper patient population when administered by qualified professionals who have undergone the appropriate training.

Physiological Responses to Acute Cycling With Blood Flow Restriction

Aerobic exercise with blood flow restriction (BFR) can improve muscular function and aerobic capacity. However, the extent to which cuff pressure influences acute physiological responses to aerobic exercise with BFR is not well documented. We compared blood flow, tissue oxygenation, and neuromuscular responses to acute cycling with and without BFR. Ten participants completed four intermittent cycling (6 × 2 min) conditions: low-load cycling (LL), low-load cycling with BFR at 60% of limb occlusion pressure (BFR60), low-load cycling with BFR at 80% of limb occlusion pressure (BFR80), and high-load cycling (HL). Tissue oxygenation, cardiorespiratory, metabolic, and perceptual responses were assessed during cycling and blood flow was measured during recovery periods. Pre- to post-exercise changes in knee extensor function were also assessed. BFR60 and BFR80 reduced blood flow (~33 and ~ 50%, respectively) and tissue saturation index (~5 and ~15%, respectively) when compared to LL (all p < 0.05). BFR60 resulted in lower VO2, heart rate, ventilation, and perceived exertion compared to HL (all p < 0.05), whereas BFR80 resulted in similar heart rates and exertion to HL (both p > 0.05). BFR60 and BFR80 elicited greater pain compared to LL and HL (all p < 0.05). After exercise, knee extensor torque decreased by ~18 and 40% for BFR60 and BFR80, respectively (both p < 0.05), and was compromised mostly through peripheral mechanisms. Cycling with BFR increased metabolic stress, decreased blood flow, and impaired neuromuscular function. However, only BFR60 did so without causing very severe pain (>8 on pain intensity scale). Cycling with BFR at moderate pressure may serve as a potential alternative to traditional high-intensity aerobic exercise.

A Useful Blood Flow Restriction Training Risk Stratification for Exercise and Rehabilitation

Blood flow restriction training (BFRT) is a modality with growing interest in the last decade and has been recognized as a critical tool in rehabilitation medicine, athletic and clinical populations. Besides its potential for positive benefits, BFRT has the capability to induce adverse responses. BFRT may evoke increased blood pressure, abnormal cardiovascular responses and impact vascular health. Furthermore, some important concerns with the use of BFRT exists for individuals with established cardiovascular disease (e.g., hypertension, diabetes mellitus, and chronic kidney disease patients). In addition, considering the potential risks of thrombosis promoted by BFRT in medically compromised populations, BFRT use warrants caution for patients that already display impaired blood coagulability, loss of antithrombotic mechanisms in the vessel wall, and stasis caused by immobility (e.g., COVID-19 patients, diabetes mellitus, hypertension, chronic kidney disease, cardiovascular disease, orthopedic post-surgery, anabolic steroid and ergogenic substance users, rheumatoid arthritis, and pregnant/postpartum women). To avoid untoward outcomes and ensure that BFRT is properly used, efficacy endpoints such as a questionnaire for risk stratification involving a review of the patient's medical history, signs, and symptoms indicative of underlying pathology is strongly advised. Here we present a model for BFRT pre-participation screening to theoretically reduce risk by excluding people with comorbidities or medically complex histories that could unnecessarily heighten intra- and/or post-exercise occurrence of adverse events. We propose this risk stratification tool as a framework to allow clinicians to use their knowledge, skills and expertise to assess and manage any risks related to the delivery of an appropriate BFRT exercise program. The questionnaires for risk stratification are adapted to guide clinicians for the referral, assessment, and suggestion of other modalities/approaches if/when necessary. Finally, the risk stratification might serve as a guideline for clinical protocols and future randomized controlled trial studies.

The feasibility, safety, and efficacy of upper limb garment-integrated blood flow restriction training in healthy adults

Background

Blood flow restriction training (BFR) has been demonstrated to increase muscle hypertrophy and strength, but has logistical and cost barriers. Garment-integrated BFR has the potential to reduce these barriers by lowering equipment demands and cost. The primary aim of the study was to explore the feasibility of garment-integrated BFR in the upper limb of healthy adults, with a secondary aim of exploring safety and efficacy.

Methods

Physically active and otherwise healthy participants with no previous experience with BFR were sought. Eligible participants completed a five-week garment-integrated BFR programme that involved completing two sessions per week. Feasibility was determined by a priori defined thresholds for recruitment, adherence to the garment-integrated BFR programme, and data collection. Safety was determined by recording adverse events and by monitoring for total arterial occlusion pressure using a fingertip pulse oximeter. Efficacy was determined by measuring push-ups to volitional failure, arm girth, and number of prescribed repetitions completed. Feasibility and safety outcomes were reported descriptively or as a proportion with associated 95% confidence intervals (95% CI). Mean change, 95% CIs, and associated effect sizes were calculated for efficacy outcomes.

Results

Twenty-eight participants were included (15 men, 13 women; mean age 31.6 years [±9.1]) and 27 successfully completed the study. Participants were successfully recruited within three months and 278/280 sessions were successfully completed (adherence=99.3%, 95% CI 97.4%, 99.9%). Minimal adverse events were reported; one incident of localised bruising (0.36%, 95% CI 0.06%, 2.0%) and three incidences of excessive pain during or post-exercise from two separate participants (1.07%, 95% CI 0.03%, 3.1%). 82/2240 pulse oximeter readings were not recorded (3.7%, 95% CI 2.9%, 4.5%). Mean push-ups to volitional failure increased by 40% (mean change=8.0, 95% CI 6, 10, d=1.40). Mean arm girth and number of prescribed repetitions completed were unchanged.

Conclusions

Garment-integrated BFR is feasible and has no signal of important harm in the upper limb of healthy adults, and could proceed to a future trial with stop/go criteria for randomisation. Further work is required to investigate the efficacy of garment-integrated BFR and determine its equivalence or superiority compared to existing BFR methods.

Blood flow restriction with different load levels in patients with knee osteoarthritis: protocol of a randomized controlled trial

Background

The effectiveness of blood flow restriction training (BFR) in elderly with knee osteoarthritis (OA) is comparable to performing high-intensity protocols (70 to 80% of 1 RM [repetition maximum]) that are known to be effective for improving the muscle strength of knee extensors, with the advantage of generating less particular rating of perceived exertion and pain immediately after training. However, despite being a promising alternative, little is known about the best way to apply the BFR, such as level of pressure and combination or not with other therapeutic modalities. The purpose of this study is to evaluate whether different levels of blood flow restriction with low load (BFR + LL) and no load (BFR + rest) are non-inferior to high-intensity resistance exercise (HIRE+BFRplacebo) for pain reduction in patients with knee OA.

Methods/design

This clinical trial is a non-inferiority, five-arm, randomized, active-controlled, single trial which will be carried out in 165 patients of both sexes with knee OA, aged 50 years and older. Participants will be randomly allocated into 5 exercise groups (40% of BFR + LL; 80% of BFR + LL; 40% of BFR + rest; 80% BFR + rest, and HIRE+BFR placebo). A mixed linear model will be used to examine the effect of group-by-time interaction on pain intensity on the WOMAC subscale (primary outcome) and on disease severity, physical functional data, balance data, quality of life, global perceived effect scale, and muscle strength (secondary outcomes). Participants will be analyzed for intention-to-treat, and the statistical assessor blinded to the groups. The collection of outcomes 72 h after completion of the 16 weeks of interventions will be the primary measurement point. Follow-up secondary timepoints will be collected at 20, 28, 40, 52, and 64 weeks after the end of interventions, except for pain during the training, which will be measured immediately at the end of each session. Only the comparison of the primary outcome between the HIRE group with each BFR group will be analyzed in the non-inferiority framework, the other comparisons between the BFR groups for the primary outcome, and all secondary outcomes will be interpreted in the superiority framework.

Discussion

The results of this clinical trial can point out more clearly to ways to optimize the BFR training with the minimum of pain immediately after training, which will allow the offer of an effective and more adherent strengthening training to patients with knee OA.

Trial registration

Registro Brasileiro de Ensaios Clínicos, RBR-93rx9q. Registered on 23 July 2020. Version 1.0.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-05998-3.

A bibliometric analysis study of blood flow restriction using CiteSpace

[Purpose] To assess the current state-of-the-art and the prevailing trends regarding the global use of blood flow restriction (BFR) in the past 20 years. [Participants and Methods] We retrieved literature relating to BFR from 1999 to 2020 using Web of Science. We conducted a bibliometric analysis of countries/institutions, cited journals, authors/cited authors, cited references, and keywords using CiteSpace. An analysis of counts and centrality was used to examine publication output, countries/institutions, core journals, active authors, foundation references, hot topics, and frontiers. [Results] Seven hundred seventy five references were included and the total number of publications has been continually increasing over the investigated period. Representatives of important academic groups are the Japanese scholars from the University of Tokyo as represented by Takashi Abe. Jeremy Paul Loenneke’s article (centrality: 0.15) was the most representative and symbolic reference with the highest centrality. The three topics identified were intervention (intensity resistance exercise, IRE), physiology (ischemia and muscular function) and behavior (adaptation and increase). The four frontier topics were phosphorylation, reduction, low intensity and arterial occlusion. [Conclusion] This study provides an insight into BFR and offers valuable information for BFR researchers to identify new perspectives for potential cooperation with collaborators and their related cooperative institutions.

Effect of Exercise on Secondary Sarcopenia: A Comprehensive Literature Review

Simple Summary

Sarcopenia is an inevitable component of aging. It is officially recognized as a muscle disease with an ICD-10-MC diagnosis code that can be used to bill for care in some countries. Sarcopenia can be classified into primary or age-related sarcopenia and secondary sarcopenia. The condition is referred to as secondary sarcopenia when any other comorbidities are present in conjunction with aging. Secondary sarcopenia is more prevalent than primary sarcopenia and requires special attention. Exercise interventions may help in our understanding and prevention of sarcopenia with a specific morbidity Glomerular filtration rate that exercise improves muscle mass, quality or physical function in elderly subjects with cancer, type 2 diabetes, kidney diseases and lung diseases. In this review, we summarize recent research that has studied the impact of exercise on patients with secondary sarcopenia, specifically those with one comorbid condition. We did not discover any exercise intervention specifically for subjects with secondary sarcopenia (with one comorbidity). Even though there is a strong argument for using exercise to improve muscle mass, quality or physical function in subjects with cancer, type 2 diabetes, kidney diseases, lung diseases and many more, very few studies have reported baseline sarcopenia assessments. Based on the trials summarized in this review, we may propose but not conclude that resistance, aerobic, balance training or even walking can be useful in subjects with secondary sarcopenia with only one comorbidity due to the limited number of trials. This review is significant because it reveals the need for broad-ranging research initiatives involving secondary sarcopenic patients and highlights a large secondary sarcopenia research gap.

Abstract

Background: Sarcopenia has been recognized as an inevitable part of aging. However, its severity and the age at which it begins cannot be predicted by age alone. The condition can be categorized into primary or age-related sarcopenia and secondary sarcopenia. Sarcopenia is diagnosed as primary when there are no other specific causes. However, secondary sarcopenia occurs if other factors, including malignancy or organ failure, are evident in addition to aging. The prevalence of secondary sarcopenia is far greater than that of primary sarcopenia and requires special attention. To date, nutrition and exercise have proven to be the best methods to combat this disease. The impact of exercise on subjects suffering from sarcopenia with a specific morbidity is worthy of examination for understanding and prevention. The purpose of this review, therefore, is to summarize recent research that has investigated the impact of exercise in patients with secondary sarcopenia, specifically with one comorbidity. Methods: Pubmed, Web of Science, Embase and Medline databases were searched comprehensively with no date limit for randomized controlled trials. The literature was specifically searched for clinical trials in which subjects were sarcopenic with only one comorbidity participating in an exercise intervention. The most visible comorbidities identified and used in the search were lung disease, kidney disease, heart disease, type 2 diabetes, cancer, neurological diseases, osteoporosis and arthritis. Results: A total of 1752 studies were identified that matched the keywords. After removing duplicates, there were 1317 articles remaining. We extracted 98 articles for full screening. Finally, we included 21 relevant papers that were used in this review. Conclusion: Despite a strong rationale for using exercise to improve muscle mass, quality or physical function in subjects with cancer, type 2 diabetes, kidney disease, lung disease and many more, baseline sarcopenia evaluation has been reported in very few trials. The limited number of studies does not allow us to conclude that exercise can improve sarcopenia in patients with other comorbidities. This review highlights the necessity for wide-ranging research initiatives involving secondary sarcopenic patients.

The Evolution of Blood Flow Restricted Exercise

The use of blood flow restricted (BFR) exercise has become an accepted alternative approach to improve skeletal muscle mass and function and improve cardiovascular function in individuals that are not able to or do not wish to use traditional exercise protocols that rely on heavy loads and high training volumes. BFR exercise involves the reduction of blood flow to working skeletal muscle by applying a flexible cuff to the most proximal portions of a person’s arms or legs that results in decreased arterial flow to the exercising muscle and occluded venous return back to the central circulation. Safety concerns, especially related to the cardiovascular system, have not been consistently reported with a few exceptions; however, most researchers agree that BFR exercise can be a relatively safe technique for most people that are free from serious cardiovascular disease, as well as those with coronary artery disease, and also for people suffering from chronic conditions, such as multiple sclerosis, Parkinson’s, and osteoarthritis. Potential mechanisms to explain the benefits of BFR exercise are still mostly speculative and may require more invasive studies or the use of animal models to fully explore mechanisms of adaptation. The setting of absolute resistive pressures has evolved, from being based on an individual’s systolic blood pressure to a relative measure that is based on various percentages of the pressures needed to totally occlude blood flow in the exercising limb. However, since several other issues remain unresolved, such as the actual external loads used in combination with BFR, the type of cuff used to induce the blood flow restriction, and whether the restriction is continuous or intermittent, this paper will attempt to address these additional concerns.

Postoperative Use of Blood Flow Restriction in Orthopedics

Blood flow restriction (BFR) therapy is being used more frequently for rehabilitation from orthopedic injuries. Several physiologic mechanisms of action, at local and systemic levels, have been proposed. Numerous studies have investigated the effects of BFR training in healthy athletes; however, limited clinical data exist supporting the use of BFR after surgery. Given that BFR training may facilitate muscle development using low-load resistance exercises, it offers a unique advantage for the post-surgical patient who cannot tolerate traditional high resistance training. [Orthopedics. 2021;44(6):e694-e698.].

Time to Save Time: Beneficial Effects of Blood Flow Restriction Training and the Need to Quantify the Time Potentially Saved by Its Application During Musculoskeletal Rehabilitation

The main goal of musculoskeletal rehabilitation is to achieve the pre-injury and/or pre-surgery physical function level with a low risk of re-injury. Blood flow restriction (BFR) training is a promising alternative to conventional therapy approaches during musculoskeletal rehabilitation because various studies support its beneficial effects on muscle mass, strength, aerobic capacity, and pain perception. In this perspective article, we used an evidence-based progressive model of a rehabilitative program that integrated BFR in 4 rehabilitation phases: (1) passive BFR, (2) BFR combined with aerobic training, (3) BFR combined with low-load resistance training, and (4) BFR combined with low-load resistance training and traditional high-load resistance training. Considering the current research, we propose that a BFR-assisted rehabilitation has the potential to shorten the time course of therapy to reach the stage where the patient is able to tolerate resistance training with high loads. The information and arguments presented are intended to stimulate future research, which compares the time to achieve rehabilitative milestones and their physiological bases in each stage of the musculoskeletal rehabilitation process. This requires the quantification of BFR training-induced adaptations (eg, muscle mass, strength, capillary-to-muscle-area ratio, hypoalgesia, molecular changes) and the associated changes in performance with a high measurement frequency (≤1 week) to test our hypothesis. This information will help to quantify the time saved by BFR-assisted musculoskeletal rehabilitation. This is of particular importance for patients, because the potentially accelerated recovery of physical functioning would allow them to return to their work and/or social life earlier. Furthermore, other stakeholders in the health care system (eg, physicians, nurses, physical therapists, insurance companies) might benefit from that with regard to work and financial burden.

Blood Flow Restriction Therapy Impact on Musculoskeletal Strength and Mass

Background

Blood flow restriction (BFR) training restricts arterial inflow and venous outflow from the extremity and can produce gains in muscle strength at low loads. Low-load training reduces joint stress and decreases cardiovascular risk when compared with high-load training, thus making BFR an excellent option for many patients requiring rehabilitation.

Indications

Blood flow restriction has shown clinical benefit in a variety of patient populations including healthy patients as well as those with osteoarthritis, anterior cruciate ligament reconstruction, polymyositis/dermatomyositis, and Achilles tendon rupture.

Technique Description

This video demonstrates BFR training in 3 clinical areas: upper extremity resistance training, lower extremity resistance training, and low-intensity cycling. All applications of BFR first require determination of total occlusion pressure. Upper extremity training requires inflating the tourniquet to 50% of total occlusion pressure, while lower extremity exercises use 80% of total occlusion pressure. Low-load resistance training exercises follow a specific repetition scheme: 30 reps followed by a 30-second rest and then 3 sets of 15 reps with 30-seconds rest between each. During cycle training, 80% total occlusion pressure is used as the patient cycles for 15 minutes without rest.

Results

Augmenting low-load resistance training with BFR increases muscle strength when compared with low-load resistance alone. In addition, low-load BFR has demonstrated an increase in muscle mass greater than low-load training alone and equivalent to high-load training absent BFR. A systematic review determined the safety of low-load training with BFR is comparable to traditional high-intensity resistance training. The most common adverse effects include exercise intolerance, discomfort, and dull pain which are also frequent in patients undergoing traditional resistance training. Severe adverse effects including deep vein thrombosis, pulmonary embolism, and rhabdomyolysis are exceedingly rare, less than 0.006% according to a national survey. Patients undergoing BFR rehabilitation experience less perceived exertion and demonstrate decreased pain scores compared with high-load resistance training.

Conclusion

Blood flow restriction training is an effective alternative to high-load resistance training for patients requiring musculoskeletal rehabilitation for multiple disease processes as well as in the perioperative setting. Blood flow restriction has been shown to be a safe training modality when managed by properly trained physical therapists and athletic trainers.

Is blood flow-restricted training effective for rehabilitation of a pianist with residual neurological symptoms in the upper limbs? A case study

[Purpose] We investigated whether blood flow-restricted training known as KAATSU training, was effective for rehabilitation of a pianist with residual neurological symptoms in the upper limbs. [Participant and Methods] A pianist with residual neurological symptoms in the upper body played “Revolutionary Etude” under two conditions: piano performance with (Piano-blood flow-restricted) and without (Piano-control) the restriction of blood flow to the upper limbs. In the Piano-blood flow-restricted exercise, a pressure of 130–170 mmHg was applied around the most proximal portion of both arms. The changes in upper limb circumference and muscle strength were measured before, immediately after, and 15 min after the performance. The impression of the piano performance was recorded after the Piano-blood flow-restricted exercise. [Results] Immediately after the piano performance, the forearm and upper arm circumferences had increased significantly in both arms, and the change was greater in the Piano-blood flow-restricted than in the Piano-control condition. The handgrip strength for the right arm also showed greater changes in the former than the latter. However, there were no significant differences between the two conditions regarding the handgrip strength of the left arm. [Conclusion] There is a high possibility that blood flow-restricted training is effective for rehabilitation of the pianist with residual neurological symptoms in the upper limbs.

Perceived Barriers to Blood Flow Restriction Training

Blood flow restriction (BFR) training is increasing in popularity in the fitness and rehabilitation settings due to its role in optimizing muscle mass and strength as well as cardiovascular capacity, function, and a host of other benefits. However, despite the interest in this area of research, there are likely some perceived barriers that practitioners must overcome to effectively implement this modality into practice. These barriers include determining BFR training pressures, access to appropriate BFR training technologies for relevant demographics based on the current evidence, a comprehensive and systematic approach to medical screening for safe practice and strategies to mitigate excessive perceptual demands of BFR training to foster long-term compliance. This manuscript attempts to discuss each of these barriers and provides evidence-based strategies and direction to guide clinical practice and future research.

Application and side effects of blood flow restriction technique: A cross-sectional questionnaire survey of professionals

The physiological benefits of applying blood flow restriction (BFR) in isolation or in the presence of physical exercise have been widely documented in the scientific literature. Most investigations carried out under controlled laboratory conditions have found the technique to be safe. However, few studies have analyzed the use of the technique in clinical settings.To analyze how the BFR technique has been applied by professionals working in the clinical area and the prevalence of side effects (SEs) resulting from the use of this technique.This is a cross-sectional study. A total of 136 Brazilian professionals who perform some function related to physical rehabilitation, sports science, or physical conditioning participated in this study. Participants answered a self-administered online questionnaire consisting of 21 questions related to the professional profile and methodological aspects and SEs of the BFR technique.Professionals reported applying the BFR technique on individuals from different age groups from youth (≤18 years; 3.5%) to older adults (60-80 years; 30.7%), but mainly on people within the age group of 20 to 29 years (74.6%). A total of 99.1% of the professionals coupled the BFR technique with resistance exercise. Their main goals were muscle hypertrophy and physical rehabilitation. The majority (60.9%) of interviewees reported using BFR in durations of less than 5 minutes and the pressure used was mainly determined through the values of brachial blood pressure and arterial occlusion. Moreover, 92% of professionals declared observing at least 1 SE resulting from the BFR technique. Most professionals observed tingling (71.2%) and delayed onset of muscle soreness (55.8%). Rhabdomyolysis, fainting, and subcutaneous hemorrhaging were reported less frequently (1.9%, 3.8%, and 4.8%, respectively).Our findings indicate that the prescription of blood flow restriction technique results in minimal serious side effects when it is done in a proper clinical environment and follows the proposed recommendations found in relevant scientific literature.