WHAT IS BLOOD FLOW RESTRICTION (BFR)?
Blood flow restriction training (BFR) was first introduced in 1966 and was popularized as “Kaatsu training” before the general name of BFR. It was used mostly among powerlifters and bodybuilders to increase strength and muscle hypertrophy. However, in recent years, research supports the use of BFR in the rehabilitation populations .
BFR is a tool that restricts venous blood flow return which aides in lowering the mechanical stress needed for muscle hypertrophy and strength gains. Research has shown that BFR training loads at or below 50% of 1-RM, even to as low as 20-30%, improve muscle strength and hypertrophy gains. BFR training focuses on the metabolic aspect of strength training and allows for strength gains at much lower intensities. This allows for early optimal loading intervention for healing tissue that cannot sustain the necessary higher loads that are needed for full recovery. To put this in perspective, one can do a straight leg raise exercise with BFR while tissues heals in order to get similar benefits of a traditional body weight squat.
HOW DOES BFR WORK?
There are two primary triggers to create physiological changes in muscle strength and hypertrophy: 1- Mechanical stress, 2- Metabolic stress. After acute or repeated bouts of appropriate mechanical stress to the muscles that exceeds tissue capacity, IGF-1 and mTOR hormones are released which are the driving force of muscle growth and hypertrophy. When triggered, it sends a cascade effect that activates satellite cells in the sarcolemma to proliferate and bind to the muscle cells to create new muscle fibers. To make strength and muscle hypertrophy gains through mechanical stress one must work at or above 65% of their 1- Rep Max (RM), with adaptation time ranging between 8-12 weeks. In the rehabilitation population, patients often do not tolerate this 65% of 1 RM load. Post surgical patients may not even be allowed to perform resistant training exercises for several weeks due to surgical precautions, depending on the surgery performed.
BFR training with the use of pneumatic tourniquets allows for arterial blood flow to a region while restricting venous blood flow return. This restriction creates a more robust anabolic environment for muscle growth and strength during rest periods, without joint stress or damage to non-contractile tissue.
BENEFITS
It has been demonstrated that BFR training increases the endocrine response and release of hormones such as GH and IGF-1, needed for protein synthesis, by 200-300%. This heightens the cell signaling for hypertrophy and strength gains. GH also helps with building of non-contractile tissues which is needed after surgery or a severe injury. Other key benefits of BFR training include: Decrease in pain perception up to 24 hours after use, increased recruitment of anaerobic muscle fibers, and an increase in angiogenesis, just to name a few.
INDICATIONS OF USE
The patient populations that are appropriate for the use of BFR training:
Prehab/ Rehab – Injuries including sprains/ strains, Osteoarthritis, Post-op patients such as TKA , ACL’s , RTC Repair, Non-weight bearing patients. It is great for the patient needing early strength gains to improve function while minimizing the mechanical stress to the muscle and joint.
Athletes and Strength Training – May be used during rest days to reduce mechanical load on muscles but continue to make strength gains.
General Population -Walking endurance, strength training for the aging population. Pending on health status and clinical predictions rules (see fig.1)
CONTRAINDICATIONS OF USE:
There are specific precautions to BFR training that must be adhered to. Available is a clinical prediction rule that combines medical signs, symptoms and clinical findings that predict success or failure of this procedure. Below is a list of key contraindications:
Venous thromboembolism, Impaired circulation or peripheral vascular compromise, Previous revascularization of the extremity, Extremities with dialysis access, Acidosis, Sickle cell anemia, Extremity infection, Tumor distal to the tourniquet, Medications and supplements with known clotting risks, Open fracture, Open soft tissue injuries, Post-traumatic lengthy hand reconstructions, Severe crushing injuries, Severe hypertension, Skin grafts in which all bleeding points must be readily distinguished, Vascular grafting, Cancer.
CONCLUSION
BFR venous return restriction has significant benefits within the physical therapy practice and has been shown to improve: Muscle strength and hypertrophy with low loads, aides in tissue repair, decreases pain perception up to 24 hours following use, and activates new blood vessel growth. BFR is a safe alternative to traditional resistance training by allowing up to 50% less in exercise intensity in order to gain similar physiological results. This plays a big part in achieving the necessary functional gains in the aging or injured population . It allows for early optimal loading interventions for healing tissue that cannot sustain the necessary higher loads that are needed for safe and quick recovery while minimizing injury to healing tissue.
At Wright Physical Therapy we are committed to your patient’s success and discovering new innovative solutions to help in full recovery of function. To learn more about BFR visit our website or call any of our locations throughout Idaho.
