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

Implementation and Clinical Outcomes of Blood Flow Restriction Training on Adults With Cerebral Palsy: A Case Series

BACKGROUND AND PURPOSE

Cerebral palsy (CP) is a congenital neurological disorder that causes musculoskeletal weakness and biomechanical dysfunctions. Strength training guidelines recommend at least 70% of 1-repetition maximum to increase muscle strength and mass. However, individuals with CP may not tolerate such high exercise intensity. Blood flow restriction (BFR) can induce similar gains in strength and muscle mass using loads as low as 20% to 30% 1-repetition maximum. This case series described the safety, feasibility, and acceptability of BFR in adults with CP and examined changes in muscle mass and strength.

CASE DESCRIPTION

Three male participants with gross motor function classification system level 3 CP underwent strength training using a periodized 8-week BFR protocol. Outcomes included: Safety via blood pressure during and post-BFR exercises in addition to adverse event tracking; Feasibility via number of support people and time-duration of BFR exercises; Acceptability via rate of perceived discomfort (0-10) and qualitative interviews; Muscle Mass via ultrasonographic cross-sectional area of the quadriceps and hamstring; and Strength via (1) 3-repetition maximum in the leg press and knee extension, (2) isometric knee flexor and extensor muscle force measured with a hand-held dynamometer, and (3) 30-second sit-to-stand test.

INTERVENTION

Participants replaced 2 exercises from their current regimen with seated knee extension and leg press exercises using progressively higher limb occlusion pressure and exercise intensity. Limb occlusion pressure started at 60%, by week 4 progressed to 80%, and then remained constant. The exercise repetition scheme progressed from fixed nonfailure repetition sets to failure-based repetition sets.

OUTCOMES

Blood pressure never exceeded safety threshold, and no adverse events were reported. The BFR training was time-consuming and resource-intensive, but well-tolerated by participants (rate of perceived discomfort with a mean value of 5.8, 100% protocol adherence). Strength, as measured by 3-repetition maximum testing and 30-second sit-to-stand test, increased, but isometric muscle force and muscle mass changes were inconsistent.

DISCUSSION

Blood flow restriction may be an effective means to increase strength in adults with CP who cannot tolerate high-intensity resistance training. Future research should compare BFR to traditional strength training and investigate mediators of strength changes in this population.

VIDEO ABSTRACT AVAILABLE

for more insights from the authors (see the Video, Supplemental Digital Content available at: http://links.lww.com/JNPT/A473).

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.

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.

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.

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.

Changes in Arterial Stiffness in Response to Blood Flow Restriction Resistance Training: A Narrative Review

Arterial stiffness naturally increases with age and is a known predictor of cardiovascular morbimortality. Blood flow restriction (BFR) training involves decreasing muscle blood flow by applying a strap or a pneumatic cuff during exercise. BFR induces muscle hypertrophy even at low intensities, making it an appealing option for older, untrained individuals. However, BFR use in patients with cardiovascular comorbidities is limited by the increased pressor and chronotropic response observed in hypertensive elderly patients. Furthermore, the impact of BFR on vascular function remains unclear. We conducted a comprehensive literature review according to PRISMA guidelines, summarizing available data on the acute and long-term consequences of BFR training on vascular function. Although evidence is still scarce, it seems that BFR has a mild or neutral long-term impact on arterial stiffness. However, current research shows that BFR can cause an abrupt, albeit transient, increase in PWV and central blood pressure. BFR and, preferably, lower-body BFR, should be prescribed with caution in older populations, especially in hypertensive patients who have an exacerbated muscle metaboreflex pressor response. Longer follow-up studies are required to assess the chronic effect of BFR training on arterial stiffness, especially in elderly patients who are usually unable to tolerate high-intensity resistance exercises.

Comparison of blood flow restriction training and conventional resistance training for the improvement of sarcopenia in the older adults: A systematic review and meta-analysis

Age-related sarcopenia places a tremendous burden on healthcare providers and patients' families. Blood flow restriction (BFR) training may be a promising treatment to bring sarcopenia down, and it offers numerous advantages over traditional resistance training. The purpose of this review was to compare the effects of BFR training and conventional resistance training on clinically delayed sarcopenia in the elderly. Databases such as PubMed, Web of Science, Embase, and Science Direct were searched to identify eligible studies; blinded data extraction was performed to assess study quality, and conflicts were submitted to third parties. Someone made the decision. One author used Review Manager (RevMan) 5.4 and compared it with data obtained by another author for this purpose. A total of 14 studies met the inclusion criteria for this review. The funnel plots of the studies did not show any substantial publication bias. Low-load blood flow restriction (LL-BFR) had no significant effect on muscle mass compared with high-load resistance training (HL-RT) (p ​= ​0.74, SMD ​= ​0.07, 95% CI: 0.33 to 0. 46) and LL-BFR had a significant effect on muscle strength compared with HL-RT (p ​= ​0.03, Z ​= ​2.16, SMD ​= ​-0.34, 95% CI: 0.65 to -0.03). LL-BFR showed a slight effect on mass compared to LL-RT (p ​= ​0.26, SMD ​= ​0.25, 95% CI: 0.19 to 0.69). Sensitivity analysis produced a nonsignificant change, suggesting that the results of this study are reasonable. In conclusion, the data suggest the possibility that BFR training improves age-related sarcopenia.

Blood Flow Restriction Training in Nonspecific Shoulder Pain: Study Protocol of a Crossover Randomised Controlled Trial

"Nonspecific shoulder pain" encompasses various non-traumatic musculoskeletal shoulder disorders, diverging from diagnostic terminologies that refer to precise tissue-oriented clinical diagnosis. Blood flow restriction (BFR) training, involving partial arterial inflow and complete venous outflow restriction, has exhibited acute hypoalgesic effects primarily in healthy populations by increasing their pain thresholds. This study aims to examine whether a single BFR session with low-load exercises can alleviate pain perception among nonspecific shoulder pain patients. Conducted as a single-blind crossover randomised clinical trial, 48 adults (age range: 18 to 40) presenting with nonspecific shoulder pain will partake in two trial sessions. Random assignment will place participants into BFR or sham BFR groups and ask them to perform one exercise with BFR. Subsequently, participants will complete a shoulder girdle loading regimen comprising six exercises. The second session will involve participants switching treatment groups. Pain pressure thresholds (PPTs), shoulder pain and disability via the shoulder pain and disability index (SPADI), maximal voluntary isometric contraction (MVIC) of shoulder external rotators, pain during active abduction, and peak pain during shoulder external rotation will be evaluated using the numeric pain rating scale (NPRS). Immediate post-exercise assessments will include patient-perceived pain changes using the global rating of change scale (GROC) and participant-rated perceived exertion (RPE), employing a modified Borg's scale (Borg CR10) post-BFR or sham BFR exercise session. Each session will encompass three assessment periods, and a combination of mixed-effect models and descriptive statistics will underpin the analysis. This protocol was approved by Cyprus National Bioethics Committee (ΕΕΒΚ/2023/48), and was registered in ClinicalTrials.gov (Registration number: NCT05956288). Conclusion: The anticipated outcomes of this study illuminated the acute effects of BFR training on pain perception within the context of nonspecific shoulder pain, potentially advancing strategies for managing pain intensity using BFR techniques.

Blood flow restriction as a potential therapy to restore physical function following COVID-19 infection

Accumulating evidence indicates that some COVID-19 survivors display reduced muscle mass, muscle strength, and aerobic capacity, which contribute to impairments in physical function that can persist for months after the acute phase of illness. Accordingly, strategies to restore muscle mass, muscle strength, and aerobic capacity following infection are critical to mitigate the long-term consequences of COVID-19. Blood flow restriction (BFR), which involves the application of mechanical compression to the limbs, presents a promising therapy that could be utilized throughout different phases of COVID-19 illness. Specifically, we hypothesize that: 1) use of passive BFR modalities can mitigate losses of muscle mass and muscle strength that occur during acute infection and 2) exercise with BFR can serve as an effective alternative to high-intensity exercise without BFR for regaining muscle mass, muscle strength, and aerobic capacity during convalescence. The various applications of BFR may also serve as a targeted therapy to address the underlying pathophysiology of COVID-19 and provide benefits to the musculoskeletal system as well as other organ systems affected by the disease. Consequently, we present a theoretical framework with which BFR could be implemented throughout the progression from acute illness to outpatient rehabilitation with the goal of improving short- and long-term outcomes in COVID-19 survivors. We envision that this paper will encourage discussion and consideration among researchers and clinicians of the potential therapeutic benefits of BFR to treat not only COVID-19 but similar pathologies and cases of acute critical illness.

Clinic and Home-Based Exercise with Blood Flow Restriction Resolves Thigh Muscle Atrophy after Anterior Cruciate Ligament Reconstruction with the Bone-Patellar Tendon-Bone Autograft: A Case Report

Anterior cruciate ligament reconstruction (ACLR) results in thigh muscle atrophy. Of the various interventions proposed to mitigate thigh muscle atrophy, exercise with blood flow restriction (BFR) appears safe and effective. Some literature suggests daily exposure to exercise with BFR may be indicated during the early phase of ACLR rehabilitation; this case report outlines the methodology utilized to prescribe clinic- and home-based BFR within an outpatient rehabilitation program. A 15-year-old male soccer player suffered a left knee injury involving the anterior cruciate ligament and both menisci. He underwent ACLR and completed exercise with BFR as part of his clinic- and home-based rehabilitation program, which included practical blood flow restriction during home-based rehabilitation. After 16 weeks of rehabilitation, surgical limb thigh girth values were objectively larger than the non-surgical limb (surgical, 52.25 cm; non-surgical 50 cm), as well as the multi-frequency bioelectrical impedance analysis of his lower-extremity lean body mass (surgical limb, 10.37 kg; non-surgical limb, 10.02 kg). The findings of this case report suggest that the inclusion of clinic- and home-based BFR within an outpatient rehabilitation program may be indicated to resolve thigh muscle atrophy early after ACLR.

The effectiveness of blood flow restriction training in cardiovascular disease patients: A scoping review

Therapeutic exercise is integral to the comprehensive rehabilitation of patients with cardiovascular disease and, as such, is recommended by the American Heart Association as a valuable and effective treatment method for such patients. The type of exercise applied to these patients is aerobic and resistance exercise with mild intensities and loads to avoid overloading the cardiovascular system. Blood flow restriction exercise is a novel exercise modality in clinical settings that has in many studies a similar effect on muscle hypertrophy, strength, and cardiovascular response to training at a 70% strength level without blood flow restriction. Since this exercise mode does not require high-intensity loads, it can be a safe method for improving muscle strength, cardiovascular endurance, and functionality in cardiovascular patients. Given that, the objective of this review is to assess and summarize existing evidence for the use of blood flow restriction in cardiovascular patients. A scoping review of existing clinical trials was conducted. Eleven studies were examined that suggested the use of blood flow restrictions in cardiovascular patients to achieve improvements in muscle strength, functionality, and cardiovascular parameters such as blood pressure decrease.

Knee Loading With Blood Flow Restriction Can Enhance Recovery After Total Knee Arthroplasty

Total knee arthroplasty (TKA) is one of the most performed operations in the world, especially in the elderly. Aging has a significant effect on joint cartilage, muscle strength, and muscle mass. Following a TKA, despite the significant reduction of symptoms and the improvement in mobility, muscle strength and muscle mass recovery remains a significant challenge. Restrictions that arise from the surgical procedure include joint loading, functional activities, and range of motion, along with limitations related to the age of the individual and their previous loading history, these are the significant restrictions, at least in the early stages of rehabilitation. Evidence indicates that blood flow restriction (BFR) training has significant potential to enhance recovery via implementation of low-load or low-intensity exercise. While respecting the indications and contraindications related to BFR application, the optimization of metabolic stress seems to offer a bridging therapy to heavy load while reducing pain and inflammation. Thus, the combination of BFR and low loads may improve muscular recovery (strength and mass), and aerobic training protocols appear to show significant enhancement of multiple cardiopulmonary parameters. Mounting evidence, direct and indirect, indicate that BFR training may have the potential to benefit the pre-operative and post-operative TKA rehabilitation phases and enhance functional recovery and physical abilities in the elderly.

Blood flow restriction training in South Africa - a panel discussion

Background

Blood flow restriction (BFR) training uses a cuff to partially occlude venous blood flow and improve musculoskeletal training outcomes. Over the past 25 years, numerous studies have demonstrated its relative safety and efficacy.

Objectives

Blood flow restriction training is under review by the Health Professions Council of South Africa due to safety and ethical concerns. The objective of this roundtable discussion is to gain better insight into the current use and perception of blood flow restriction training in South Africa.

Formation of panel

The expert panel had experience with the use of BFR training and included one representative from each of the following professions, namely, sports medicine, physiotherapy and biokinetics.

Discussion

The panellists provided their unique perspectives on BFR training, whilst reaching a relative consensus on its safety, screening, efficacy, and appropriate use. Agreement on appropriate loading and occlusion pressure protocols during different phases of rehabilitation was less clear.

Conclusion

Although BFR is a safe and effective modality, the development of evidence-based protocols among different health professionals in South Africa is required to ensure good clinical practice.