What is Blood Flow Restriction Therapy (BFRT) in Physiotherapy?
Blood flow restriction therapy (BFRT) is becoming a widely used rehabilitation technique, especially in resistance training or exercise. It uses a tourniquet to limit arterial inflow and obstruct venous outflow. This method was initially thought of as a tool to promote muscular development. Still, as further research is carried out on its various benefits, understanding of its physiologic advantages and mechanism of action has increased, and so have the clinical uses that are now feasible. Atrophy is the reduction in size or the wasting away of tissues or body parts. This method may quicken recovery and prevent muscle atrophy for postoperative, wounded, or load-compromised individuals. It is also a way to reduce joint stress without sacrificing strength improvements. Additionally, growing evidence shows that it improves cardiovascular health and lessens discomfort (Cognetti et al., 2022).
In both clinical and sporting settings, blood flow restriction therapy (BFRT) is a cutting-edge training technique for increasing muscle strength and hypertrophy. Hypertrophy is the increase in muscle size due to growth and an increase in muscle cells. This form of therapy prompts muscle development through several identified processes, including cellular swelling, anaerobic metabolism, and induction of type 2 muscular fibers. This is achieved when venous occlusion and low-load resistance training are combined. Patients undergoing musculoskeletal rehabilitation frequently experience muscle weakness and atrophy, which delays their return to functional activity. Traditional resistance training places stress on the connective tissues and joints, which can be harmful to senior individuals and those undergoing rehabilitation (Hodge et al., 2020).
One repetition maximum, or 1RM, is a common abbreviation for repetition maximum. This represents the highest weight you can lift in one repetition with maximum effort. Your personal best for a squat, deadlift, or other weightlifting exercise is known as a 1RM (Rogers & Laferrara, 2019). Traditional muscle development exercises demand weights of 70% of the one-repetition maximum. However, the medical literature has repeatedly demonstrated that BFRT with weights of 20% to 40% of 1RM increases muscular strength, hypertrophy, and angiogenesis. Although the rate of adverse effects has not been found to be higher than that of conventional high-load resistance training, long-term studies are still needed to assess its impact on the cardiovascular system. (Hodge et al., 2020).
Benefits of BFRT in Rehabilitation
A doctor named Dr. Yoshiaki Sato discovered this type of training in the 1970s while wearing an entire leg cast as a result of breaking his leg. He performed blood flow restriction training on his leg above the cast two to three times a day for the six weeks that the cast was on, and when the cast was removed, he managed to predominantly preserve his muscle mass. This showcased the potential this form of treatment possessed in maintaining muscle mass and preventing atrophy.
BFRT’s objective is to help patients build more strength while lifting smaller weights, which lowers the overall stress on the limbs. It also alleviates the burden of injured tendons, ligaments, muscles, and joints. Doctors and other healthcare professionals believe that BFRT may be an excellent addition to training programs (What Is Blood Flow Restriction Therapy and How Does It Work?, 2022, #).
Varied BFRT techniques have been used to examine numerous demographic subgroups, including athletes and non-athletes, healthy and wounded individuals, preoperative and postoperative patients, the elderly, and even adolescent subgroups. Resistance exercise is the most popular way to perform BFRT; this is sometimes referred to as BRF-RE. According to guidelines for skeletal muscle hypertrophy in conventional resistance training, two to three weekly BFRT sessions are advised. In the early stages of rehabilitation following an injury or surgery, a more intensive schedule, including twice-daily BFRT exercise, could potentially be a viable method to quicken recovery (Cahalin & Formiga, 2020).
Maintaining and enhancing patients’ aerobic fitness is a hallmark of getting them back into exercise or sports. Aerobic capacity can be significantly reduced during post-surgery healing. Moreover, for elderly or hospitalized patients, this aspect of physical health might be crucial to functional rehabilitation. Compared to resistance training, the research on BFRT with aerobic exercise (BFR-AE) has been limited. Still, indicators of aerobic fitness, such as relative and absolute oxygen consumption (VO2) and exercise time to exhaustion, have all been shown to increase more than they did in control groups. Additionally, even in trained athletes, low-intensity training combined with BFRT has demonstrated comparable significant gains in VO2 and strength (Cognetti et al., 2022).
Who can benefit from BFRT?
Sports trainers have used blood flow restriction to train athletes for decades. It is now also being incorporated into rehabilitation regimens by physical and occupational therapists. More healthcare professionals and researchers are investigating how blood flow restriction treatment might be utilized for rehabilitation as it grows in popularity. According to recent studies, precise recommendations for blood flow restriction therapy include the cuff’s width, material, and placement, the restriction’s pressure, workout guidelines, and the type of contractions. Specific research also identifies medical conditions for which BFRT could be utilized to recover faster (Jacob, n.d.).
According to the New York Times, a popular trend at the Tokyo Olympics in 2020 was noted to be blood flow restriction training. Both American marathon runner Galen Rupp and American swimmer Michael Andrew have been seen sporting tourniquet-like bands on their limbs to achieve BFR (Groth & Laube, 2021).
Blood flow restriction training has recently grown in popularity among sports and rehabilitation communities. Certain groups, such as those listed below, have started using this form of therapy:
- Postoperative and postoperative individuals
- Aging populations
- Individuals that are immobile or on bed rest
- Amputees
- Active subgroups in recovery
- Athletes
- Bodybuilders
More research is required to pinpoint the precise mechanism and ideal application of BFRT. However, the existing data point to a positive future for using BFRT in athletes, rehabilitation patients, or geriatric patients. It can aid in the fight against muscle atrophy and related muscle weakness (What Is Blood Flow Restriction Therapy and How Does It Work?, 2022).
On the flip side, multiple subgroups of people are not advised to use BFRT as a form of treatment. Although research indicates that BFRT is safe and that injuries from this type of training are uncommon, it has several limitations that must be considered to carry it out safely. Individuals suffering from diseases that result in poor circulation are not advised to undertake this treatment. This includes people who experience circulatory issues or clot risks such as deep vein thrombosis (DVT) or varicose veins, those who face heart disease or insufficiency, pregnant women, diabetics, children under the age of 12, those that have been diagnosed with lymphedema, or cancer survivors (Nichols, n.d.).
How is BFRT performed?
BFRT is accomplished through the use of a cuff as external pressure. In BFRT exercise, pressurized bands that resemble blood pressure cuffs are worn around the arms or legs to restrict blood flow to particular muscles while exercising. It’s believed to encourage the body to produce more muscle mass than it normally would at a specific level of exercise intensity. Periods of blood flow restriction are interspersed with rest periods during which the area’s blood flow is restored during BRFT.
Although compression devices can be used alone, this treatment is commonly administered while exercising. BFR during exercise often entails placing pressurized cuffs on the proximal (upper or lower) part of a limb. The tight band or strap on the affected limb restricts blood flow in (blood that carries oxygen) and out (blood that carries lactic acid and other waste products from muscle movement), below the amount of compression during BFR training. This momentarily depletes the muscle’s oxygen levels. Due to the shortage of oxygen, the muscles have to work harder, which increases the production of the protein synthesis necessary for both muscle growth and muscle repair. According to physicians, this type of training impacts the fast-twitch, anaerobic muscle fibers typically used for explosive actions like sprinting and jumping (Groth & Laube, 2021).
Conventionally, loads up to 70% or more of 1 RM are traditionally required for strengthening procedures. Low-load exercise of 20% to 30% of one RM is used in BFRT. A little BFRT applied to active muscles acts as a powerful stimulus to build muscle mass and strength. The majority of research on resistance training has focused on relatively low intensities (between 20 and 30 percent of one RM), high repetition counts in each set (15 to 30 reps), 3-5 sets, and 30-second rest periods in between sets. In order to reduce the complexity of the movement pattern, a large portion of the research initially concentrated on single-joint exercises. However, it has now evolved to include entire limb movement, such as walking (Jacob, n.d.).
BFRT must be administered under the supervision of a trained professional such as a physiologist or occupational therapist. This is because there are multiple aspects to consider before using it as a form of treatment. Including the cuff’s width and material, where it is placed, the pressure at which blood flow is restricted, and the workout parameters of volume, resistance, and rest (Groth & Laube, 2021).
Potential risks and limitations of BFRT
Blood flow restriction has been proven to promote muscular growth, which has been linked to metabolic buildup, during low-load resistance exercise. However, the ability of metabolites to promote muscle growth when sustained post-exercise is still unknown. One study found that applying blood flow restriction after high-load training did not promote muscle growth in either sex and instead appeared to inhibit it in women (Dankel et al., 2016).
There is a gap in the data, and there is uncertainty regarding the exact mechanisms that cause a gain in muscle mass and strength. However, various potential processes and mechanisms factor in increased muscle protein synthesis via muscle swelling. This mechanism also entails escalated muscle activation generated by metabolic accumulation-induced fatigue. One study found that a rise in the content of intramuscular inorganic phosphate may cause muscle fatigue. Additional research is required in this area (Jacob, n.d.).
Some studies highlight the safety concerns of patients using this form of therapy. Cuff pressure and exercise parameters must be closely monitored and adjusted to each patient’s threshold. Complete occlusion makes exercise painful for patients and is typically riskier than partial occlusion. When measuring pressure, the patient should be in the same posture as when the exercise is carried out, whether prone, supine, sitting, or standing. Throughout the training program, it’s crucial to periodically reassess limb pressure regardless of the pressure method you choose. This is specifically true for patients receiving blood flow restriction therapy for the first time.
Just like pressure, exercise parameters differ across the literature. BFRT uses several muscle contractions in addition to diverse kinds of training. Although concentric and eccentric exercises are typically combined, several researchers have compared concentric and eccentric exercises separately. Other research observed the difference made by changing the resistance between sets, which in turn affected the number of reps. The direction of treatment in this regard will likely come from the individual and possibly their diagnosis (Groth & Laube, 2021).
Potential risks associated with BFRT are:
- Numbness as a result of vascular occlusion
- Pain due to the tourniquet being too tight
- Bruising at the cuff site
- Permanent or temporary nerve damage
- Syncope (fainting)
- Subcutaneous hemorrhage
In extreme cases, there is a potential threat of rhabdomyolysis, a condition that may be fatal or cause indefinite disability (Nichols, n.d.).
In conclusion, BFRT promotes muscular hypertrophy through a synergistic response to mechanical and metabolic stress. There are indications of added benefits for cardiovascular health and pain management. For a faster recovery process, new BFRT variations and expanding applications in postoperative patients and athletes seem promising. The effectiveness and prescription of BFR will be improved with continued attention to rehabilitation recommendations and research into the physiology and the numerous applications of BFRT (Hughes & Patterson, 2020). Furthermore, although BFRT shows promising results, it must only be performed following the guidance of a professional. The pressure of the cuff, along with the intensity and volume of the exercise, may need to be monitored and modified according to each individual’s capability and threshold.
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References:
Cahalin, L. P., Formiga, M. F., & Fay, R. (2020, April 15). EFFECT OF AEROBIC EXERCISE TRAINING WITH AND WITHOUT BLOOD FLOW RESTRICTION ON AEROBIC CAPACITY IN HEALTHY YOUNG ADULTS: A SYSTEMATIC REVIEW WITH META-ANALYSIS. NCBI. Retrieved April 19, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7134358/
Cognetti, D. J., Sheean, A. J., & Owens, J. G. (2022, January 4). Blood Flow Restriction Therapy and Its Use for Rehabilitation and Return to Sport: Physiology, Application, and Guidelines for Implementation. National Library Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8811521/#:~:text=Blood%20flow%20restriction%20(BFR)%20is,of%20resistance%20training%20or%20exercise.
Dankel, S. J., Jessee, M. B., Abe, T., & Counts, B. R. (2016, August 1). Post-exercise blood flow restriction attenuates muscle hypertrophy. PubMed. Retrieved April 17, 2023, from https://pubmed.ncbi.nlm.nih.gov/27480315/
Groth, L., & Laube, J. (2021, July 29). Olympic Athletes Are Into Blood Flow Restriction Training. Everyday Health. Retrieved April 17, 2023, from https://www.everydayhealth.com/fitness/olympic-athletes-are-into-blood-flow-restriction-training-does-it-work/
Hodge, K. A., Vopat, L. M., Bechtold, M. M., & Hodge, K. A. (2020, June 15). Blood Flow Restriction Therapy: Where We Are and Where We Are Going. PubMed. Retrieved April 17, 2023, from https://pubmed.ncbi.nlm.nih.gov/31609881/
Hughes, L., & Patterson, S. D. (2020, April 1). The effect of blood flow restriction exercise on exercise-induced hypoalgesia and endogenous opioid and endocannabinoid mechanisms of pain modulation. PubMed. Retrieved April 19, 2023, from https://pubmed.ncbi.nlm.nih.gov/32105522/
Jacob, J. (n.d.). Blood Flow Restriction Therapy. BTE Technologies. Retrieved April 18, 2023, from https://www.btetechnologies.com/therapyspark/blood-flow-restriction-therapy/?utm_term=physical%20treatment&utm_campaign=BFR+(Conversions)&utm_source=adwords&utm_medium=ppc&hsa_acc=4258307045&hsa_cam=17633453953&hsa_grp=142186805510&hsa_ad=607929320537&hsa_
Nichols, E. (n.d.). Blood Flow Restriction Training 101. Performance Health Academy. Retrieved April 18, 2023, from https://www.performancehealthacademy.com/blood-flow-restriction-training-101.html
Rogers, P., & Laferrara, T. (2019, November 26). Repetition Maximum for Weight Training. Verywell Fit. Retrieved April 17, 2023, from https://www.verywellfit.com/what-is-repetition-maximum-and-1rm-3498379
What is Blood Flow Restriction Therapy and how does it work? (2022). Professional Physical Therapy. https://www.professionalpt.com/services/blood-flow-restriction-training-therapy-bfrt/#:~:text=The%20goal%20of%20Blood%20Flow,preventing%20disuse%20atrophy%20of%20muscles.
