
During the 2020 Summer Games in Tokyo, there were reports of elite athletes training while wearing inflatable cuffs around their muscles. American swimmer Michael Andrew, who won a gold medal in the 4×100-meter medley relay, used this new technique, called blood flow restriction exercise (BFR). Other elite athletes, including wrestler Kayla Miracle and distance runner Galen Rupp, have also used it. With excitement building around this exercise, an important question to ask is “Is BFR simply a popular trend or will it become a best practice?”
Blood flow restriction exercise was originally developed in Japan in 1966 by Yoshiaki Sato, MD, PhD, where it is known as “Kaatsu training,” which translates to “training with added pressure.” It consists of exercising with an inflatable cuff—like a tourniquet—around the arms or legs. The cuff is inflated to a moderate pressure, which partially limits blood from flowing to and from the working muscles.
The addition of blood flow restriction to otherwise moderate exercise creates a high-intensity workout for the muscles without over-stressing the joints. Using this technique leads to increased muscle size and strength while using relatively light weights. These changes occur faster with BFR than with traditional forms of exercise. In addition, people using this technique can experience quicker muscle growth with both resistance exercise, such as lifting weights, and with aerobic activities, such as walking.
Some athletes use BFR for training and injury prevention, while others are using it to aid recovery from injury. A study published in the Journal of Applied Physiology suggests that adding BFR exercise to an athlete’s existing training program may help to further enhance training outcomes. Nonathletes, including people recovering from major anterior cruciate ligament surgery, older adults with osteoarthritis and wounded soldiers may benefit from blood flow restriction, too.
Although the practice has been found to be safe, people who use BFR are likely to feel some discomfort and pain in the muscles. It is important to consult with your primary care provider, physical therapist or credentialed fitness professional when considering any new exercise program, including BFR, to make sure it is right for you.
Future research will help scientists understand more about the potential performance benefits of BFR for athletes. It could perhaps be an integral part of athlete training leading up to the 2024 Summer Games in Paris.

Jamie Phillips, MS, is a certified strength and conditioning specialist and doctoral student in the Department of Physical Therapy at Central Michigan University. He is also a Division 1 ice hockey coach and a former professional hockey player. Phillips’ interests include sports performance and injury rehabilitation in athletes.

Steven Elmer, PhD, is an associate professor in the Department of Kinesiology and Integrative Physiology at Michigan Technological University. His research uses exercise training to restore musculoskeletal function after injury, maintain health across the life span and enhance athletic performance.