Blood Flow Restriction Therapy: From Development to Applications

Acute neuromuscular and perceptual responses to blood flow restriction exercise in adults with severe haemophilia: A pilot study

INTRODUCTION

No previous studies have implemented a standard blood flow restriction (BFR) training session in people with severe haemophilia (PwH), where this type of training has been contraindicated.

AIMS

The purpose of this study was to evaluate the tolerability, adverse events, and neuromuscular and perceptual responses to an acute session of low load (LL) knee extensions with BFR in PwH under prophylaxis.

METHODS

Eight PwH performed one LL-BFR session with 40% arterial occlusion pressure (AOP). Perceptual responses and adverse effects were assessed, together with high-density surface electromyography of vastus medialis (VM) and lateralis (VL).

RESULTS

Significant normalized root mean square differences were found within each set, but not between sets. Spatial distribution (centroid displacement (p > .05), modified entropy (VM, set two, cycles three and five, p = .032) and coefficient of variation (VM, set two, cycles four and five lower than cycle three (p = .049; p = .036)) showed changes within each set. Median frequency showed a slight increase during cycle four of set four (p = .030). Rate of perceived exertion slightly increased with each set while tolerability slightly decreased in the last set and fear of training with BFR generally decreased after the session.

CONCLUSIONS

In PwH, a LL-BFR session at 40% AOP is safe and feasible. Our results suggest that potential muscle impairments may blunt neuromuscular adaptations induced by BFR.

Blood Flow Restriction Training in Patients With Rotator Cuff Tendinopathy: A Randomized, Assessor-Blinded, Controlled Trial

OBJECTIVES

To investigate the effects of low-load blood flow restriction (BFR) training on shoulder muscle thickness, rotator cuff (RC) strength, and shoulder symptoms in patients with RC tendinopathy.

DESIGN

A randomized, assessor-blinded, controlled trial.

SETTINGS

Physiotherapy clinic at a university.

PARTICIPANTS

Twenty-eight patients were randomized into an 8-week (2 times/week) shoulder rehabilitation, that is, BFR or non-BFR group.

INTERVENTIONS

BFR training.

MAIN OUTCOME MEASURES

(1) RC, deltoid, scapula retractor, and biceps muscle thicknesses and shoulder internal rotation (IR) and external rotation (ER) strengths. (2) Shoulder pain/function.

RESULTS

The BFR group had a greater increase in biceps muscle thickness ( P = 0.002) and shoulder IR strength at 60 degrees/s ( P = 0.040) than the non-BFR group. No differences between the 2 groups were observed in other measurements. Significant improvements in supraspinatus, infraspinatus, and scapula retractor muscle thicknesses and in shoulder ER and IR strengths were observed over time in both the groups (all P < 0 .05). Also, shoulder pain decreased and shoulder function increased over time in both the groups (all P < 0 .05).

CONCLUSIONS

Low-load BFR training resulted in a greater increase in biceps thickness and shoulder IR strength compared with the non-BFR group in patients with RC tendinopathy. However, there was no superiority of either exercise training regarding the RC, scapula retractor, deltoid muscle thicknesses, or improvements in shoulder ER strength and shoulder pain/function.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

The study was registered in ClinicalTrials.gov named Blood Flow Restriction Training in Patients with Shoulder Pain and the registration number is NCT04333784.

Use of blood flow restriction for increasing the strength of the ischiocrural muscles in anterior cruciate ligament rehabilitation: A case report

BACKGROUND

The hamstring muscles have a key function in the stability of the knee, limiting the anterior translation of the tibia. Therefore, to better perform rehabilitation after anterior cruciate ligament (ACL) surgery, it is important to develop a specific program based on hamstring strength recovery. It is possible to increase strength and muscle hypertrophy through high load exercises (HL); the recommended load is about 60%-80% of a maximum repetition (MR). Although low-load resistance training (LL) is ineffective at reproducing these values, the use of Blood Flow Restriction (BFR) with LL exercises appears to allow athletes to increase strength and muscle hypertrophy. This could limit functional decline and mitigate muscle atrophy allowing to optimize the recovery path and load management in post-operative patients. Recent scientific evidence, as far as the increasingly frequent use of BFR in rehabilitation and sports rehabilitation is concerned, suggests that these devices could represent one of the most significant innovations in the physiotherapy field. The aim of this study was to increase the strength of the hamstrings in the early phases of ACL rehabilitation with an LL-BFR training protocol for speeding up the development of adequate muscle strength.

CASE DESCRIPTIONS

The patient, a 25-year-old male professional footballer, suffered from ACL injury during a football match, and after three months, he underwent a reconstruction ACL surgery with medial Hamstring tendon autograft. The athlete engaged a pre-operative program to restore a full active and passive knee range of motion and increase muscular strength. The first rehabilitation phase was supported by the adoption of BFR for hamstring strengthening, starting from the sixth week post-surgery (T0). A complete assessment of posterior hamstring muscles was performed through a hand-held dynamometer and load detection platforms. Three different types of exercises, focusing on the hamstring muscles, were chosen. Two further assessments were performed over time (T1 ant T2), highlighting different changes that occurred.

RESULTS

Interesting results showed a significant increase between T0 and T1 for all the assessed outcomes; in this case an average increase in strength of 59.87% between the beginning and the end of 4 weeks rehabilitation protocol was obtained in the first interval (T0-T1), while only 25.26% resulted in the second interval (T1-T2). However, the collected data should be considered with caution due to some limitations: the single experience of a single patient can hardly be generalized. Moreover, the reliance on isometric measurement of maximal strength and the absence of a direct strength measurement of the hamstrings during squat remain questionable.

CONCLUSION

The final results suggest the capacity of the LL-BFR exercises to recreate a condition of a high intensity muscular effort with respect to load management, especially after surgery. This highlights the need to further investigate BFR adoption as it allows the patients to speed up their rehabilitation goals in developing adequate muscle strength.

The effects of upper body blood flow restriction training on muscles located proximal to the applied occlusive pressure: A systematic review with meta-analysis

BACKGROUND

Blood flow restriction combined with low load resistance training (LL-BFRT) is associated with increases in upper limb muscle strength and size. The effect of LL-BFRT on upper limb muscles located proximal to the BFR cuff application is unclear.

OBJECTIVE

The aim of this systematic review was to evaluate the effect of LL-BFRT compared to low load, or high load resistance training (LL-RT, HL-RT) on musculature located proximal to cuff placement.

METHODS

Six electronic databases were searched for randomized controlled trials (RCTs). Two reviewers independently evaluated the risk of bias using the PEDro scale. We performed a meta-analysis using a random effects model, or calculated mean differences (fixed-effect) where appropriate. We judged the certainty of evidence using the GRADE approach.

RESULTS

The systematic literature searched yielded 346 articles, of which 9 studies were eligible. The evidence for all outcomes was of very low to low certainty. Across all comparisons, a significant increase in bench press and shoulder flexion strength was found in favor of LL-BFRT compared to LL-RT, and in shoulder lean mass and pectoralis major thickness in favor of the LL-BFRT compared to LL-RT and HL-RT, respectively. No significant differences were found between LL-BFRT and HL-RT in muscle strength.

CONCLUSION

With low certainty LL-BFRT appears to be equally effective to HL-RT for improving muscle strength in upper body muscles located proximal to the BFR stimulus in healthy adults. Furthermore, LL-BFRT may induce muscle size increase, but these adaptations are not superior to LL-RT or HL-RT.

Patellar Tendinopathy: Critical Analysis Review of Current Nonoperative Treatments

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Patellar tendinopathy is an attritional injury of the patellar tendon that is frequently identified in jumping athletes. Through repetitive or explosive movements, considerable loads and high peak strains are generated across the patellar tendon.

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This leads to microinjury of tendon fibers, local mucoid degeneration, and loss of the fibrocartilaginous tissue that attaches tendon to bone.

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Management of patellar tendinopathy often begins with nonoperative modalities: progressive tendon loading and eccentric rehabilitative exercise programs are the most effective. While a variety of additional treatment modalities are available, the comparative efficacy of these supportive treatments is not well differentiated at this time.

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In this article, we analyze the existing literature regarding nonoperative treatment of patellar tendinopathy and provide additional insight on the effectiveness of current modalities.

Effect of Blood Flow Restriction on Functional, Physiological and Structural Variables of Muscle in Patients with Chronic Pathologies: A Systematic Review

The main objective of this systematic review of the current literature is to analyze the changes that blood flow restriction (BFR) causes in subjects with neuro-musculoskeletal and/or systemic pathologies focusing on the following variables: strength, physiological changes, structural changes and cardiocirculatory variables. The search was carried out in seven databases, including randomized clinical trials in which therapeutic exercise was combined with the blood flow restriction tool in populations with musculoskeletal pathologies. Outcome variables are strength, structural changes, physiological changes and cardiocirculatory variables. Twenty studies were included in the present study. Although there is a lot of heterogeneity between the interventions and evaluation instruments, we observed how the restriction of blood flow presents significant differences in the vast majority of the variables analyzed. In addition, we observed how BFR can become a supplement that provides benefits when performed with low intensity, similar to those obtained through high-intensity muscular efforts. The application of the BFR technique can provide benefits in the short and medium term to increase strength, muscle thickness and cardiovascular endurance, even improving the physiological level of the cardiovascular system. In addition, BFR combined with low-load exercises also achieves benefits comparable to high-intensity exercises without the application of BFR, benefiting patients who are unable to lift high loads.

Rotator cuff strength is not augmented by blood flow restriction training

OBJECTIVE

Blood flow restriction (BFR) training utilizes a tourniquet applied to the upper or lower extremities (UE or LE) to occlude blood flow while exercising. BFR training may help augment strength in muscles that are proximal to BFR cuff application. However, prior studies have failed to demonstrate augmented strength gains in the rotator cuff when the tourniquet is applied to the UE. The purpose of this study was to evaluate if a protocol consisting of LE exercises, performed with BFR, followed by rotator cuff exercises was superior in augmenting strength, and cross-sectional area (CSA) of the rectus femoris, in untrained subjects when compared to a non-BFR training group.

DESIGN

Randomized controlled trial.

SETTING

University.

PARTICIPANTS

Thirty-five subjects (mean age 25.8 ± 1.6 y) randomized to a BFR or non-BFR group.

MAIN OUTCOME MEASURES

Muscular strength measured via hand held dynamometer and the CSA of the dominant rectus femoris was measured by diagnostic ultrasound.

RESULTS

Both groups experienced significant gains in LE and rotator cuff strength. Strength increased in the BFR group by 11.6% for the supraspinatus, 34.1% for shoulder ER, 23.4% for the quadriceps, and 17.1% for the hamstrings. Strength increased in the non-BFR group by 7.3% for the supraspinatus, 20% for shoulder ER, 12.8% for the quadriceps, and 10.7% for the hamstrings. However, there were no differences in strength gains between groups. Neither group experienced a significant increase in CSA for the rectus femoris.

CONCLUSION

The BFR protocol used in this study did not augment strength for the rotator cuff in subjects who also performed LE exercises under occlusion.

Enhancing Adaptations to Neuromuscular Electrical Stimulation Training Interventions

Neuromuscular electrical stimulation (NMES) applied to skeletal muscles is an effective rehabilitation and exercise training modality. However, the relatively low muscle force and rapid muscle fatigue induced by NMES limit the stimulus provided to the neuromuscular system and subsequent adaptations. We hypothesize that adaptations to NMES will be enhanced by the use of specific stimulation protocols and adjuvant interventions.

Current Clinical Concepts: Blood Flow Restriction Training

Muscle weakness and atrophy are common impairments following musculoskeletal injury. The use of blood flow restriction (BFR) training offers the ability to mitigate weakness and atrophy without overloading healing tissues. This approach requires consideration of a wide range of parameters and the purpose of this manuscript is to provide insights into proposed mechanisms of effectiveness, safety considerations, application guidelines, and clinical guidelines for BFR training following musculoskeletal injury. BFR training appears to be a safe and effective approach to therapeutic exercise in sports medicine environments. While training with higher loads produces the most substantial increases in strength and hypertrophy, BFR training appears to be a reasonable option to bridge between earlier phases of rehabilitation when higher loads may not be tolerated by the patient and later stages that are consistent with return to sport performance.