Postoperative rehabilitation exercises with addition of blood flow restriction therapy following olecranon fracture: A case report.

BACKGROUND: The addition of blood flow restriction therapy (BFRT) to exercise in patients with olecranon fracture treated surgically has not been described in the literature. PURPOSE: To describe the effects and safety of BFRT exercises in the postoperative rehabilitation of a patient with olecranon fracture. CASE PRESENTATION: A 27-year-old male with a surgically treated olecranon fracture completed a 12-week postoperative physical therapy programme. The assessment was performed at the start of rehabilitation, 4 and 12 weeks. The patient had elbow pain, decreased active range of motion (AROM), reduced handgrip strength, and limited physical function. The patient was treated with low-intensity resistance exercises with BFRT. The BFRT was applied with three exercises per stage, at 50% of the limb occlusion pressure and 75 repetitions per exercise. At discharge from physical therapy, improvements were observed in pain intensity (5.9-1.4 cm), AROM of elbow flexion (88°-137°) and extension (-22°--2°), AROM of forearm pronation (18°-68°) and supination (34°-78°), handgrip strength (8 kg-47 kg), physical function (22.9%-89.6%), and disability (72.7%-13.6%). These changes reached the minimal clinically important difference at the time of discharge for all measures, except for extension, pronation, and supination AROM. CONCLUSION: The addition of BFRT to exercise was effective in improving pain, elbow, and wrist AROM, handgrip strength, function, and disability in a patient with surgically treated olecranon fracture. Despite the inherent limitations of our design, we believe these preliminary findings are compelling to warrant future investigations.

Body position and cuff size influence lower limb arterial occlusion pressure and its predictors: implications for standardizing the pressure applied in training with blood flow restriction.

Background: Arterial occlusion pressure (AOP) is a relevant measurement for individualized prescription of exercise with blood flow restriction (BFRE). Therefore, it is important to consider factors that may influence this measure. Purpose: This study aimed to compare lower limb AOP (LL-AOP) measured with 11 cm (medium) and 18 cm (large) cuffs, in different body positions, and explore the predictors for each of the LL-AOP measurements performed. This information may be useful for future studies that seek to develop approaches to improve the standardization of pressure adopted in BFRE, including proposals for equations to estimate LL-AOP. Methods: This is a cross-sectional study. Fifty-one healthy volunteers (males, n = 25, females, n = 26; Age: 18-40 years old) underwent measurement of thigh circumference (TC), brachial blood pressure, followed by assessments of LL-AOP with medium and large cuffs in positions supine, sitting and standing positions. Results: The large cuff required less external pressure (mmHg) to elicit arterial occlusion in all three-body positions when compared to the medium cuff (p < 0.001). The LL-AOP was significantly lower in the supine position, regardless of the cuff used (p < 0.001). Systolic blood pressure was the main predictor of LL-AOP in the large cuff, while TC was the main predictor of LL-AOP with the medium cuff. Body position influenced strength of the LL-AOP predictors. Conclusion: Our results indicate that LL-AOP and its predictors are substantially influenced by body position and cuff width. Therefore, these variables should be considered when standardizing the pressure prescribed in BFRE.

Effects of endurance training combined with blood flow restriction on functionality in older adults: a systematic review / Efeitos do treinamento de resistência combinado com restrição de fluxo sanguíneo na funcionalidade de idosos: uma revisão sistemática

The aim of this review was to verify the effects of aerobic exercise combined with blood flow restriction on older adult functionality. Systematic searches were performed in PubMed, Web of Science, and Embase between July and December 2023. Randomized studies with participants aged ≥ 60 years who were evaluated before and after the experimental protocols were included. We registered this systematic review at the International Prospective Register (PROSPERO CRD42022347205). The search strategy identified 2698 studies, four of which were included in the review, with 80 participants. The results suggested that aerobic exercise combined with blood flow restriction increased performance on specific functional tests. However, these results should be interpreted with caution due to the low-to-moderate study quality, as well as the low number of participants and studies. In conclusion, aerobic exercise and blood flow restriction may increase functional capacity in older adults. Further studies are needed to confirm such findings. (AU)

Concerns about the application of resistance exercise with blood-flow restriction and thrombosis risk in hemodialysis patients.

BACKGROUND: Hemodialysis (HD) per se is a risk factor for thrombosis. Considering the growing body of evidence on blood-flow restriction (BFR) exercise in HD patients, identification of possible risk factors related to the prothrombotic agent D-dimer is required for the safety and feasibility of this training model. The aim of the present study was to identify risk factors associated with higher D-dimer levels and to determine the acute effect of resistance exercise (RE) with BFR on this molecule. METHODS: Two hundred and six HD patients volunteered for this study (all with a glomerular filtration rate of <15 mL/min/1.73 m2). The RE + BFR session consisted of 50% arterial occlusion pressure during 50 min sessions of HD (intradialytic exercise). RE repetitions included concentric and eccentric lifting phases (each lasting 2 s) and were supervised by a strength and conditioning specialist. RESULTS: Several variables were associated with elevated levels of D-dimer, including higher blood glucose, citrate use, recent cardiovascular events, recent intercurrents, higher inflammatory status, catheter as vascular access, older patients (>70 years old), and HD vintage. Furthermore, RE + BFR significantly increases D-dimer after 4 h. Patients with borderline baseline D-dimer levels (400-490 ng/mL) displayed increased risk of elevating D-dimer over the normal range (≥500 ng/mL). CONCLUSION: These results identified factors associated with a heightened prothrombotic state and may assist in the screening process for HD patients who wish to undergo RE + BFR. D-dimer and/or other fibrinolysis factors should be assessed at baseline and throughout the protocol as a precautionary measure to maximize safety during RE + BFR.

Effect of High-Intensity Interval Exercise versus Continuous Low-Intensity Aerobic Exercise with Blood Flow Restriction on Psychophysiological Responses: A Randomized Crossover Study.

This study compared the effect of continuous low-intensity aerobic exercise with blood flow restriction (LI-AE-BFR) versus high-intensity interval exercise (HIIE), matching total external mechanical work between conditions, on perceptual (exertion, pain, affective and pleasure) and physiological responses (heart rate [HR], blood lactate [BL] and muscle fatigue). Ten healthy untrained men (25.6 ± 3.78 years old; 75.02 ± 12.02 kg; 172.2 ± 6.76 cm; 24.95 ± 3.16 kg/m²) completed three visits to the laboratory. In visit 1, anthropometry, blood pressure and peak running velocity on the treadmill were measured. In visits 2 and 3, participants were randomly assigned to HIIE or LI-AE-BFR, both in treadmill. HIIE consisted of 10 one-minute stimuli at 80% of peak running velocity interspersed with one-minute of passive recovery. LI-AE-BFR consisted of 20-minutes of continuous walking at 40% of peak running velocity with bilateral cuffs inflated to 50% of arterial occlusion pressure. BL and maximum isometric voluntary contraction (MIVC - fatigue measure) were measured pre- and immediately post-exercise. HR, rating of perceived exertion (RPE), and rating of perceived pain (RPP) were recorded after each stimulus in HIIE and every two minutes in LI-AE-BFR. Affective response to the session, pleasure, and future intention to exercise (FIE) were assessed 10 minutes after the intervention ended. Increases in BL concentrations were greater in HIIE (p = 0.028; r = 0.51). No effects time or condition were reported for MIVC. HR was higher in HIIE at all analyzed time points (p < 0.001; d = 3.1 to 5.2). RPE did not differ between conditions (p > 0.05), while average session RPP was higher in LI-AE-BFR (p = 0.036; r = 0.46). Affective positive response (p = 0.019; d = 0.9) and FIE (p = 0.013; d = 0.97) were significantly higher in HIIE. Therefore, HIIE elicited higher physiological stress, positive affective response, and intention to engage in future exercise bouts compared to LI-AE-BFR.

Ischemic preconditioning increases spinal excitability and voluntary activation during maximal plantar flexion contractions in men.

The enigmatic benefits of acute limb ischemic preconditioning (IP) in enhancing muscle force and exercise performance have intrigued researchers. This study sought to unravel the underlying mechanisms, focusing on increased neural drive and the role of spinal excitability while excluding peripheral factors. Soleus Hoffmann (H)-reflex /M-wave recruitment curves and unpotentiated supramaximal responses were recorded before and after IP or a low-pressure control intervention. Subsequently, the twitch interpolation technique was applied during maximal voluntary contractions to assess conventional parameters of neural output. Following IP, there was an increase in both maximum normalized force and voluntary activation (VA) for the plantar flexor group, with negligible peripheral alterations. Greater benefits were observed in participants with lower VA levels. Despite greater H-reflex gains, soleus volitional (V)-wave and sEMG amplitudes remained unchanged. In conclusion, IP improves muscle force via enhanced neural drive to the muscles. This effect appears associated, at least in part, to reduced presynaptic inhibition and/or increased motoneuron excitability. Furthermore, the magnitude of the benefit is inversely proportional to the skeletal muscle's functional reserve, making it particularly noticeable in under-recruited muscles. These findings have implications for the strategic application of the IP procedure across diverse populations.

Effects of blood flow restriction therapy in patients with knee osteoarthritis: protocol for an overview of systematic reviews.

Background: Osteoarthritis (OA) is the most common and prevalent musculoskeletal disease associated with population aging, negatively impacting function and quality of life. A consequence of knee OA is quadriceps muscle weakness. Musculoskeletal rehabilitation using low load exercises, associated with Blood Flow Restriction (BFR) may be a useful alternative to high load exercises when those cannot be tolerated. Several systematic reviews have reported inconclusive results due to discrepancies in study findings, heterogeneity of results, evaluated time points, and research questions explored. Objective: To perform an overview of systematic reviews with meta-analyses, synthesizing the most recent evidence on the effects of muscle strength training with BFR for knee OA. Methodology: Systematic reviews that include primary controlled and randomized clinical trials will be considered for inclusion. Articles will be considered only if they present a clear and reproducible methodological structure, and when they clearly demonstrate that a critical analysis of the evidence was carried out using instrumented analysis. Narrative reviews, other types of review, overviews of systematic reviews, and diagnostic, prognostic and economic evaluation studies will be excluded. Studies must include adults aged 40 years and older with a diagnosis of knee OA. Two authors will perform an electronic search with guidance from an experienced librarian. The following databases will be searched: PubMed via MEDLINE, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), PEDro, Cumulative Index to Nursing and Allied Health Literature (CINAHL) via EBSCO host, Web of Science, and the gray literature. The search strategy used in the databases will follow the acronym PICOS (population, intervention, comparison, outcome, and study design). Screening (i.e., titles and abstracts) of studies identified by the search strategy will be selected using Rayyan (http://rayyan.qcri.org). The quality assessment will be performed using the "Assessment of Multiple Systematic Reviews" (AMSTAR-2) tool. Systematic Review Registration: PROSPERO, CRD42022367209.

Ischemic Preconditioning Improves the Bench-Press Maximal Strength in Resistance-Trained Men.

We investigated whether acute ischemic preconditioning (IPC) would affect upper limb maximal strength performance in resistance-trained men. Using a counterbalanced randomized crossover design, fifteen men (29.9 ± 5.9 yrs.; 86.3 ± 9.6 kg; 8.0 ± 5.0 yrs. resistance training experience) performed one-repetition maximum (1-RM) bench press tests on three different occasions: control, 10 min post-IPC or 10 min post-placebo (SHAM). One-way analysis of variance showed that the post-IPC condition increased (P < 0.0001) 1-RM loads compared to both control and post-SHAM (control 113.3 ± 15.9 kg vs. SHAM 113.9 ± 15.8 kg vs. IPC 115.7 ± 15.6 kg), while control and SHAM did not differ (P > 0.05). Individual results showed that 13 participants (~87%) improved their performance post-IPC compared to control, and 11 participants (~73%) performed better post-IPC compared to post-SHAM. Reported session rating of perceived exertion (RPE) was lower (P < 0.0001) post-IPC (8.5 ± 0.6 arb.u) compared to control (9.3 ± 0.5 arb.u) and post-SHAM (9.3 ± 0.5 arb.u). Therefore, we conclude that IPC acutely improves upper limb maximal strength performance and reduces session-RPE in resistance-trained men. These results suggest an acute ergogenic effect of IPC for strength and power sports such as powerlifting.

Cardiovascular and Perceptual Responses to Resistance Training with Practical Blood Flow Restriction Induced by a Non-Elastic Band vs. Pneumatic Cuff: A Crossover Randomized Study.

Our purpose in this study was to analyze perceptual and cardiovascular responses in low-load resistance training (RT) sessions associated with a fixed non-elastic band compressed to the proximal region of the arms (p-BFR) versus a pneumatic cuff inflated to a pressure of 150 mmHg (t-BFR). Participants (16 healthy trained men) were randomly assigned to two conditions of low-load RT (20% one repetition maximum [1RM]) with BFR (p-BFR or t-BFR). In both conditions, the participants performed five exercises (4 sets/30-15-15-15) for the upper-limbs, but in one of the conditions, the exercises were performed with a p-BFR induced by a non-elastic band, while in the other, the exercises were performed with a t-BFR using a device with similar width. The devices used to generate the BFR had similar widths (5 cm). Brachial blood pressure (bBP) and heart rate (HR) were measured before, after each exercise and after the experimental session (5-, 10-, 15-, and 20 min post-session). Rating of perceived exertion (RPE) and rating of pain perception (RPP) were reported after each exercise and 15 minutes post-session. HR increased during the training session in both conditions, with no differences between p-BFR and t-BFR. Neither intervention increased diastolic BP (DBP) during training, but there was a significant post-session reduction in DBP in the p-BFR, with no differences observed between conditions. There were no significant differences in RPE and RPP in the two training conditions, with both conditions associated with higher RPE and RPP at the end versus beginning of the experimental session. We conclude that when BFR device width and material are similar, low-load training with t-BFR and p-BFR promotes similar acute perceptual and cardiovascular responses in healthy trained men.

Creatine supplementation combined with blood flow restriction training enhances muscle thickness and performance: a randomized, placebo-controlled, and double-blind study.

This study aimed to compare the effects of an 8-week creatine (CR) or placebo (PL) supplementation on muscle strength, thickness, endurance, and body composition employing different training paradigms with blood flow restriction (BFR) vs. traditional resistance training (TRAD). Seventeen healthy males were randomized between the PL (n = 9) and CR (n = 8) groups. Participants were trained unilaterally utilizing a within-between subject bicep curl exercise where each arm was allocated to TRAD or BFR for 8 weeks. Muscular strength, thickness, endurance, and body composition were evaluated. Creatine supplementation promoted increases in muscle thickness in TRAD and BFR compared with their placebo counterparts, however, without a significant difference between treatments (p = 0.349). TRAD training increased maximum strength (1 repetition maximum (1RM)) compared with BFR after 8 weeks of training (p = 0.021). Repetitions to failure at 30% of 1RM were increased in the BFR-CR group compared with the TRAD-CR group (p = 0.004). Repetitions to failure at 70% 1RM were increased from weeks 0-4 (p < 0.05) and 4-8 (p < 0.05) in all groups. Creatine supplementation exerted a hypertrophic effect when utilized with TRAD and BFR paradigms and increased muscle performance at 30% 1RM when utilized in conjunction with BFR. Therefore, creatine supplementation seems to amplify muscle adaptation following a BFR program. Registered in the Brazilian Registry of Clinical Trials (ReBEC), under the registration number: RBR-3vh8zgj.

Acute Effect of Resistance Training With Blood Flow Restriction on Perceptual Responses: A Systematic Review and Meta-Analysis.

CONTEXT: Several studies have compared perceptual responses between resistance exercise with blood flow restriction and traditional resistance exercise (non-BFR). However, the results were contradictory. OBJECTIVES: To analyze the effect of RE+BFR versus non-BFR resistance exercise [low-load resistance exercise (LL-RE) or high-load resistance exercise (HL-RE)] on perceptual responses. DATA SOURCES: CINAHL, Cochrane Library, PubMed®, Scopus, SPORTDiscus, and Web of Science were searched through August 28, 2021, and again on August 25, 2022. STUDY SELECTION: Studies comparing the effect of RE+BFR versus non-BFR resistance exercise on rate of perceived exertion (RPE) and muscle pain/discomfort were considered. Meta-analyses were conducted using the random effects model. STUDY DESIGN: Systematic review and meta-analysis. LEVEL OF EVIDENCE: Level 2. DATA EXTRACTION: All data were reviewed and extracted independently by 2 reviewers. Disagreements were resolved by a third reviewer. RESULTS: Thirty studies were included in this review. In a fixed repetition scheme, the RPE [standardized mean difference (SMD) = 1.04; P < 0.01] and discomfort (SMD = 1.10; P < 0.01) were higher in RE+BFR than in non-BFR LL-RE, but similar in sets to voluntary failure. There were no significant differences in RPE in the comparisons between RE+BFR and non-BFR HL-RE; after sensitivity analyses, it was found that the RPE was higher in non-BFR HL-RE in a fixed repetition scheme. In sets to voluntary failure, discomfort was higher in RE+BFR versus non-BFR HL-RE (SMD = 0.95; P < 0. 01); however, in a fixed scheme, the results were similar. CONCLUSION: In sets to voluntary failure, RPE is similar between RE+BFR and non-BFR exercise. In fixed repetition schemes, RE+BFR seems to promote higher RPE than non-BFR LL-RE and less than HL-RE. In sets to failure, discomfort appears to be similar between LL-RE with and without BFR; however, RE+BFR appears to promote greater discomfort than HL-RE. In fixed repetition schemes, the discomfort appears to be no different between RE+BFR and HL-RE, but is lower in non-BFR LL-RE.

Ischemic preconditioning and exercise performance: are the psychophysiological responses underestimated?

The findings of the ischemic preconditioning (IPC) on exercise performance are mixed regarding types of exercise, protocols and participants' training status. Additionally, studies comparing IPC with sham (i.e., low-pressure cuff) and/or control (i.e., no cuff) interventions are contentious. While studies comparing IPC versus a control group generally show an IPC significant effect on performance, sham interventions show the same performance improvement. Thus, the controversy over IPC ergogenic effect may be due to limited discussion on the psychophysiological mechanisms underlying cuff maneuvers. Psychophysiology is the study of the interrelationships between mind, body and behavior, and mental processes are the result of the architecture of the nervous system and voluntary exercise is a behavior controlled by the central command modulated by sensory inputs. Therefore, this narrative review aims to associate potential IPC-induced positive effects on performance with sensorimotor pathways (e.g., sham influencing bidirectional body-brain integration), hemodynamic and metabolic changes (i.e., blood flow occlusion reperfusion cycles). Overall, IPC and sham-induced mechanisms on exercise performance may be due to a bidirectional body-brain integration of muscle sensory feedback to the central command resulting in delayed time to exhaustion, alterations on perceptions and behavior. Additionally, hemodynamic responses and higher muscle oxygen extraction may justify the benefits of IPC on muscle contractile function.

Blood flow restriction therapy applied to sports training / Terapia de restrição do fluxo sanguíneo aplicada ao treinamento esportivo / Terapia de restricción del flujo sanguíneo aplicada al entrenamiento deportivo

ABSTRACT Introduction: Blood flow restriction therapy, also known as KAATSU pressurization training or ischemic exercise training is a controlled method of vascular occlusion combined with resistance training, with the great growth of its research in recent years. Regular strength training, prevention of lean mass loss, and post-operative rehabilitation are some areas in which the therapy has been prominent. It is believed that it can also be beneficial in sports performance. Objective: Study the effects of an intervention with blood flow restriction therapy on athletes during training. Methods: 32 college athletes with more than two years of experience in sports training, free of injuries, and 20±3 years old were volunteers. They were randomly divided into groups A (no pressure), B (training pressure), C (intermittent pressure), D (full compression). Results: The athletes in the no pressurization group, intermittent pressurization group, training pressurization group, and full-time pressurization group showed significant differences (P<0.05). It can be considered that there is a significant difference in the muscular endurance indexes of the athletes in the non-compression group before and after training, while the athletes in the non-compression group achieved a significant increase in muscular endurance after 6 weeks of training Conclusion: Blood flow restriction therapy can effectively enhance the training effect with various strength qualities, and play a role as a promoter of hypertrophy and vascularization. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução: A terapia de restrição do fluxo sanguíneo, também conhecida como treinamento de pressurização da KAATSU ou treinamento de exercício isquêmico é um método controlado de oclusão vascular combinado ao treino de resistência, com grande crescimento de suas pesquisas nos últimos anos. Treinos regulares de força, prevenção de perda de massa magra e reabilitação pós-operatória são algumas áreas em que a terapia tem se destacado. Acredita-se que possa ser benéfica também no desempenho esportivo. Objetivo: Estudar os efeitos de uma intervenção com terapia de restrição do fluxo sanguíneo nos atletas durante o treinamento. Métodos: Foram voluntários 32 atletas universitários com mais de dois anos de experiência em treinamento esportivo, livres de lesões e com 20±3 anos de idade. Foram divididos aleatoriamente em grupos A (sem pressão), B (pressão de treinamento), C (pressão intermitente), D (compressão integral). Resultados: Os atletas do grupo sem pressurização, do grupo de pressurização intermitente, do grupo de pressurização de treinamento e do grupo de pressurização em tempo integral, mostraram diferenças significativas (P<0,05). Pode-se considerar que existe uma diferença significativa nos índices de resistência muscular dos atletas do grupo sem compressão antes e depois do treinamento, enquanto os atletas do grupo sem compressão conseguiram um aumento significativo na resistência muscular após 6 semanas de treinamento Conclusão: A terapia de restrição do fluxo sanguíneo pode efetivamente melhorar o efeito de treinamento com várias qualidades de força, além de desempenhar um papel como promotor de hipertrofia e vascularização. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción: La terapia de restricción del flujo sanguíneo, también conocida como entrenamiento de presurización KAATSU o entrenamiento de ejercicio isquémico es un método controlado de oclusión vascular combinado con entrenamiento de resistencia, con gran crecimiento de su investigación en los últimos años. El entrenamiento regular de la fuerza, la prevención de la pérdida de masa magra y la rehabilitación postoperatoria son algunas de las áreas en las que la terapia se ha destacado. Se cree que también puede ser beneficioso para el rendimiento deportivo. Objetivo: Estudiar los efectos de una intervención con terapia de restricción del flujo sanguíneo en atletas durante el entrenamiento. Métodos: 32 atletas universitarios con más de dos años de experiencia en el entrenamiento deportivo, libres de lesiones y con 20±3 años de edad fueron voluntarios. Se dividieron aleatoriamente en los grupos A (sin presión), B (presión de entrenamiento), C (presión intermitente), D (compresión total). Resultados: Los atletas del grupo sin presurización, del grupo con presurización intermitente, del grupo con presurización de entrenamiento y del grupo con presurización a tiempo completo mostraron diferencias significativas (P<0,05). Se puede considerar que existe una diferencia significativa en los índices de resistencia muscular de los atletas del grupo sin compresión antes y después del entrenamiento, mientras que los atletas del grupo sin compresión lograron un aumento significativo de la resistencia muscular después de 6 semanas de entrenamiento Conclusión: La terapia de restricción del flujo sanguíneo puede mejorar eficazmente el efecto del entrenamiento con diversas cualidades de fuerza, y desempeñar un papel como promotor de la hipertrofia y la vascularización. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.

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 Effect of a Single Bout of Resistance Exercise with Blood Flow Restriction on Arterial Stiffness in Older People with Slow Gait Speed: A Pilot Randomized Study.

Purpose: Low-intensity resistance exercise with moderate blood-flow restriction (LIRE-BFR) is a new trending form of exercises worldwide. The purpose of this study was to compare the acute effect of a single bout of traditional resistance exercise (TRE) and LIRE-BFR on arterial stiffness in older people with slow gait speeds. Methods: This was a randomized, controlled clinical study. Seventeen older adults (3 men; 14 women; 82 ± 5 years old) completed a session of TRE (n = 7) or LIRE-BFR (n = 10). At baseline and after 60 min post-exercise, participants were subject to blood pressure measurement, heart rate measurements and a determination of arterial stiffness parameters. Results: There was no significant difference between the TRE and LIRE-BFR group at baseline. Pulse-wave velocity increased in both groups (p < 0.05) post-exercise with no between-group differences. Both exercise modalities did not produce any adverse events. The increase in systolic blood pressure, pulse pressure, augmentation pressure and pulse wave velocity (all p > 0.05) were similar after both TRE and LIRE-BFR. Conclusion: TRE and LIRE-BFR had similar responses regarding hemodynamic parameters and pulse-wave velocity in older people with slow gait speed. Long-term studies should assess the cardiovascular risk and safety of LIRE-BFR training in this population.

Does Blood Flow Restriction Therapy Improve Leg Strength in Patients With a Painful Total Knee Arthroplasty?

BACKGROUND: Blood flow restriction (BFR) therapy has been proposed to help patients build strength with fewer repetitions than standard physical therapy (PT). We sought to determine if BFR would improve quadriceps and hamstring strength in patients with instability and perceived weakness >1 year after primary total knee arthroplasty (TKA). METHODS: We retrospectively reviewed 48 patients with painful TKAs and flexion instability as well as quadriceps and hamstring weakness who performed a 6-week PT program and received isokinetic strength measurements (ISMs). Thirty-six patients completed a standard PT program (non-BFR) and 12 patients completed a BFR regimen. ISMs were taken before and after PT to quantify quadriceps and hamstring power, torque, and work compared to the contralateral leg. Statistical analysis was conducted on pre-PT and post-PT ISMs and decisions for revision surgery. RESULTS: There were no differences in ISMs after PT between the BFR and non-BFR groups. The non-BFR group showed statistically significant strength improvements in flexion but not extension (+28.7%-32.8%, P = .0145-.255). Although no significant difference was found in the BFR group, they saw improvements in all extension strength metrics (19.4%-23.4%, P = .3315-.3901) and flexion (25.7%-29.9%, P = .1994-.2392). No difference was observed between the groups in the rates of subsequent revision TKA (8.3% vs 16.7%, P = .3362). CONCLUSION: BFR did not improve quadriceps and hamstring strength compared to PT alone in patients with instability and weakness after TKA. Over 80% of total patients chose to avoid revision TKA after completion of focused PT with or without BFR.

Entrenamiento con restricción al flujo sanguíneo / Blood flow restriction training

RESUMEN El entrenamiento con restricción al flujo sanguíneo es un método de entrenamiento que implica la aplicación de un dispositivo de envoltura próxima al músculo a entrenar, y realizar repeticiones con cargas inferiores a las recomendadas tradicionalmente para lograr hipertrofia y el aumento de fuerza muscular. Este entrenamiento ha ganado popularidad dentro de la kinesiología gracias a que permite alcanzar dichos objetivos en pacientes donde no es posible realizar cargas mayores debido a su condición clínica. El objetivo de este paso a paso es describir el procedimiento para su aplicación y detallar las contraindicaciones que presenta la técnica.

ABSTRACT Blood-flow restriction training is a training technique that involves the application of a blood pressure cuff proximally to the muscle that is being trained and low-load training to elicit hypertrophy and increase muscle strength. This training technique has become popular among physical therapists, since both goals are attainable in patients unable to do high-load training due to their clínical condition. This study aims to describe the procedure of this technique and detail any contraindications.

Low load strength training, associated with or without blood flow restriction increased NO production and decreased production of reactive oxygen species in rats aorta.

Studies have shown that strength training (ST) with blood flow restriction (BFR) in which low load is used (20-50% of 1 maximum voluntary contraction - MVC) can produce positive adaptations similar to ST with loads equal to or greater than 70% 1 MVC. Furthermore, recent studies have investigated the effects of STBFR on muscle adaptations, but few studies investigated the effects of STBFR on vascular function. This study aimed to evaluate the effects of the STBFR program on the vascular reactivity of the abdominal aorta of Wistar rats with femoral arteriovenous blood flow restriction. Male rats were divided into four groups: sedentary sham (S/S), sedentary with blood flow restriction (S/BFR), trained sham (T/S), and trained with blood flow restriction (T/BFR). The animals in the S/BFR and T/BFR groups underwent surgery to BFR in the femoral artery and vein. After one week, the trained groups started the ST which consisted of climbing ladder, six sets of 10 repetitions with 50% of 1 MVC assessed by maximum loaded weight (MLW) carried out for four weeks. Concentration-response curves to Acetylcholine (ACh: 10 nM - 100 µM) and Phenylephrine (PHE: 1 nM - 30 µM) were performed in aortic rings with intact endothelium. The production of nitric oxide (NO) and reactive oxygen species (ROS) in situ and the vascular remodeling marker (MMP-2) were also measured. The ST increased the strength of the T/S and T/BFR groups in MLW tests. The S/BFR group showed a 22% reduction in relaxation to acetylcholine, but exercise prevented this reduction in the T/BFR group. In animals without BFR, ST did not alter the response to acetylcholine. An increase in NO production was seen in T/S and T/BFR showed a reduction in ROS production (62% and 40%, respectively). In conclusion low load ST with BFR promotes similar vascular function responses to ST without BFR. Low load ST with and without BFR is interventions that can improve performance with similar magnitudes. Both training methods could have some benefits for vascular health due to NO production in the aorta increased in the T/S group and decreased production of reactive oxygen species in the T/BFR group.

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.

Metabolic and hormonal responses to chronic blood-flow restricted resistance training in chronic kidney disease: a randomized trial.

Maintenance of glycemic and lipemic homeostasis can limit the progression of diabetic kidney disease. Resistance training (RT) is effective in controlling glycemia and lipemia in kidney disease; however, the effect of RT with blood flow restriction (RT+BFR) on these metabolic factors has not been investigated. We aimed to verify if chronic (6 months) RT and RT+BFR performed by patients with stage-2 chronic kidney disease (CKD) improves their glycemic homeostasis and immunometabolic profiles. Patients with CKD under conservative treatment (n = 105 (33 females)) from both sexes were randomized into control (n = 35 (11 females); age 57.6 ± 5.2 years), RT (n = 35 (12 females); age 58.0 ± 6.2 years), and RT+BFR (n = 35 (10 females); 58.0 ± 6.4 years) groups. Chronic RT or RT+BFR (6 months) was performed 3 times per week on non-consecutive days with training loading adjusted every 2 months, RT 50%-60%-70% of 1RM, and RT+BFR 30%-40%+50% of 1RM and fixed repetition number. Renal function was estimated with the glomerular filtration rate and serum albumin level. Metabolic, hormonal, and inflammatory assessments were analyzed from blood samples. Six months of RT and RT+BFR were similarly effective in improving glucose homeostasis and hormone mediators of glucose uptake (e.g., irisin, adiponectin, and sirtuin-1), decreasing pro-inflammatory and fibrotic proteins, and attenuating the progression of estimated glomerular filtration rate. Thus, RT+BFR can be considered an additional exercise modality to be included in the treatment of patients with stage 2 chronic kidney disease. Trial registration number: U1111-1237-8231. URL: http://www.ensaiosclinicos.gov.br/rg/RBR-3gpg5w/, no. RBR-3gpg5w. Novelty: Glycemic regulation induced by resistance training prevents the progression of CKD. Chronic RT and RT+BFR promote similar changes in glycemic regulation. RT and RT+BFR can be considered as non-pharmacological tools for the treatment of CKD.