Blood flow restriction (or “BFR”) is a physical therapy modality that restricts blood flow to a muscle. BFR requires the application of a device similar to a blood pressure cuff or tourniquet to safely compress the blood vessels underneath. The goal is to use apply enough pressure to completely restrict the venous blood flow (blood LEAVING the muscle), while allowing arterial blood flow (blood going into the muscle). When done correctly, blood ends up pooling in the muscle beyond the tourniquet, creating a hypoxic environment in which the tissue is deprived of oxygen. This lack of oxygen is said to increase growth hormones, muscle hypertrophy, and muscle strength.
Hypoxic training is not a new trend. If you’ve ever heard of someone training at altitude for a competition or race, the principle behind BFR is similar—the body is forced to compensate due to the lack of oxygen. In fact, “weight-lifters have been tapping into the benefits of BFR for years,” says Eric Bowman, M.D., M.P.H., assistant professor of orthopedic surgery and rehabilitation at Vanderbilt University Medical Center in Franklin, TN.
While research demonstrates that BFR can decrease muscle atrophy on its own, physical therapists typically incorporate exercise with the use of the BFR cuff. The biggest benefit of BFR is that muscular gains can be attained without the stress of high loads weight or resistance. Simple, low-load exercises can produce a similar muscle burn to traditional heavier weight training.
With traditional exercise, we need to lift 70-85% of our one repetition maximum to achieve increased strength or muscle growth. With BFR, we can produce similar results at only 20-35% of our one rep max. Talk about a significant difference!
This is particularly useful for patients who have weight-lifting restrictions or are experiencing pain as they progress through a strengthening program. In general, BFR training helps to reduce the amount of stress placed on the applied limb.
Prior to including BFR in your plan of care, an experienced physical therapist will carefully consider the indications and contraindications, and work closely with your prescribing physician.
Follow along next week as we dive deeper into the use of BFR for physical therapy patients, and discuss who is a good candidate and who should steer clear.
- Slysz, Joshua et al. “The efficacy of blood flow restricted exercise: A systematic review & meta-analysis.” Journal of Science and Medicine in Sport, Volume 19, Issue 8, 669 – 675, September 2015.
- Patterson, Stephen D et al. “Blood Flow Restriction Exercise: Considerations of Methodology, Application and Safety.” Frontiers if Physiology, Volume 10, 533, May 2019.
- “Personalized Blood Flow Restriction.” Owens Recovery Science – Blood Flow Restriction Training, www.owensrecoveryscience.com/.