A look at the origin of the treatment, and whether or not it's something triathletes should look to for marginal gains.

Blood Flow Restriction (BFR) is when specific pressure is applied during low-load training exercise to create anabolic (growth) changes in muscle. The goal of the therapy is to allow oxygenated blood to the working muscles while restricting venous return, thus creating a metabolic overload similar to that of heavy load training. In other words, participants get the sought after “muscle burn” achieved during heavy training, without the risks associated with using heavy weights.

Department of Defense researchers in Texas first used Blood Flow Restriction while trying to help wounded soldiers salvage limbs. Veterans who sustained blast trauma needed to build limb strength to avoid amputation. Following success with this population, Blood Flow Restriction was then used to try to regenerate tissue in veterans who’d lost chunks of muscle. This research led to its first use on a pro athlete, NFL player Jadeveon Clowney, who was recovering from a cartilage injury. His success with it spread rapid adoption through NFL, MLB, NBA, NHL, and Division I colleges.

So does it work? Multiple studies have consistently shown that Blood Flow Restriction does improve muscle size and functional strength. Additionally, low-load training is significantly safer on injured joints than weight training, allowing strengthening to start earlier in the rehab process and with greater strength gains than conventional strengthening alone. For patients rehabilitating from an injury, Blood Flow Restriction can play a helpful role.

For the trained athlete looking for the next “cool factor” to provide marginal gains, is it worth it? Yes and No. Blood Flow Restriction does allow for greater strengthening of the muscles, while helping protect joints as the athlete is training with lower loads. However, restrictive bands are used only on the upper arm or upper leg, limiting strength gains to those limbs. For multisport athletes, muscle strength and balance across a number of joints are important. Also, Blood Flow Restriction’s benefits are greatest when following a protocol. Proper equipment (bands with specific pressure gauges) and supervision are required. Although consumers can buy restrictive bands to self tourniquet and exercise, it’s essential to establish an initial program with a professional.

Casey Maguire is a Los Angeles-based orthopedic physical therapist who has treated professional triathletes, cyclists, and multiple athletes in the NBA, NHL, NFL, and USTA. His focus is on functional biomechanics.