Blood Flow Restriction Therapy (BFR)
Blood flow restriction therapy is an innovative treatment method intended to help someone gain muscle strength and hypertrophy by lifting lighter loads on an injured limb. The physical therapist (PT) secures a strap around the patient’s injured extremity to serve as a tourniquet and sets it to the appropriate pressure. This feels somewhat like a blood pressure cuff on your leg or arm.
So how does restricting blood flow aid in healing an injury? When the cuff is set to the appropriate pressure, blood flow from the heart to the extremity will remain unrestricted, but the blood flowing back to the heart is reduced by about 50-80% — this is where the restriction takes place (it is not restricting blood flow to the working muscle.) This change in blood flow allows the patient to lift a lighter load that is more appropriate for an injured limb while gaining the strength benefits as if they were lifting heavier — almost like “tricking” the muscle. As we know, lifting heavier weights helps to increase muscle size. BFR therefore allows an atrophied muscle that has wasted away due to inactivity to hypertrophy. When the muscle hypertrophies, it can allow for more movement, greater functional strength, and speed up overall recovery.
BFR is commonly used with post-op patients because muscle mass can be quickly lost after surgery or when a limb is immobilized. BFR helps the quadriceps (the muscles that straighten the knee and is very important for walking) hypertrophy after a knee injury, like an anterior cruciate ligament (ACL) tear. On average it takes about 9 months (sometimes up to 12 months) to fully recover from an ACL tear, so BFR can be a valuable rehab tool.
Blood flow restriction therapy was invented in Japan in 1966, but has gained in popularity over the past few years. And like with most interventions, there are several precautions with BFR. Contraindications include pregnancy, deep vein thrombosis (DVT), varicose veins, high blood pressure, cardiac disease, and rhabdomyolysis. If you have any of these conditions, it is important that your PT knows prior to treatment, so that the best plan can be curated for you.
Overall, BFR is a great way to gain muscle strength and hypertrophy, as long as you don’t have any of the conditions listed above. BFR is not recommended to use outside of the clinic or for everyday use, as it can become dangerous or strenuous on your body. This intervention is to help those who have compromised extremities due to an injury maintain or gain muscle strength throughout the recovery process. It has also been proven that it actually speeds up the rehab process too!