Blood Flow Restriction
Blood Flow Restriction (BFR) is being readily used for rehabilitation and strength training in the United States. Research studies show the beneficial effects of blood flow restriction on building/maintaining muscle, decreasing recovery times, reducing pain, and improving function. And, in our fast paced lives where every minute counts, BFR can accomplish these gains in a 15 minute session, 2-4x week.
BFR uses basic physiological principles to improve strength and endurance with less strain on the body. By reducing blood flow to an extremity for short periods of time, the body is stimulated to release beneficial hormones that aid in strength, recovery, angiogenesis (formation of additional blood vessels), and pain modulation. BFR has been shown to improve the release of Human Growth Hormone (HGH), Insulin-like Growth Factor (IGF-1), Vascular Endothelial Growth Factor (VEGF),and VO2 max.
When implementing BFR, the goal is to restrict arterial blood flow by applying a tight cuff to the upper arm or thigh to reduce the amount of new, oxygen-rich blood reaching the muscles. Additionally, BFR prevents deoxygenated venous blood from returning to the heart. This causes a build-up of waste products, such as Hydrogen ions, in the muscle tissue. The build-up of these waste products, along with restricting oxygenated blood from reaching the muscle, has been shown to create a prime environment for stimulating muscle growth within the body.
During BFR, slow-twitch (type 1) muscle fibers are starved of oxygen sooner than their fast-twitch (type 2) counterparts, causing slow-twitch muscle fibers to fatigue first, and fast-twitch (type 2) fibers to take over sooner and more rapidly. The fast twitch fibers are the muscle fibers in our bodies that grow and produce muscle mass more quickly and easily. Therefore, BFR can be utilized with no weights or low weight strength training to elicit the benefits of heavy weight training. For some patients, BFR can be safer than traditional weight training, as lower weights are utilized, potentially reducing the chance of physical injury from lifting heavy loads and reducing the amount of physical/mechanical stress on muscles, ligaments, and joints, making it an excellent option for those with arthritis, joint pain, or injuries.
BFR can also be used in beneficial ways for endurance athletes. Using BFR with endurance exercise like rowing machines, treadmills, arm ergometers, or stationary bikes may speed up time to exhaustion, improve aerobic capabilities, increase VO2 max, and improve muscle strength. Additionally, BFR has been shown to improve peak running velocity, secondary to improved running economy and more efficient oxygen consumption. For the most beneficial effects, the heart rate should increase to at least 40% of maximum heart rate during BFR endurance exercise, and only be used for up to 15 minutes continuously, before allowing for reperfusion. As with strength training, a maximum of 3-4 endurance training sessions utilizing BFR should be performed each week.