Blood flow restriction training is becoming more popular in the training and rehabilitation world. It is a very useful technique that helps patients recover faster and more efficiently, especially for those who are limited in lifting heavier weights. This is great news for people who might not be able to tolerate heavy weight, such as the elderly, people with chronic diseases and those rehabbing from injury or surgery. BFRT has also been shown to decrease the effects of muscle atrophy (loss of muscle) for those who cannot lift heavy weights. When used correctly, BFRT can be a key component of any rehabilitation.
The Evidence: BFR training originates from the creation of Kaatsu training by Dr. Yoshiako Sato, and since then, a growing body of evidence has supported the use of blood flow restriction training. The theory behind BFRT is to partially occlude blood flow to a limb, as well as to allow blood pooling in the limb. This deprives the muscle tissue of oxygen, which may sound like a bad thing but this environment is similar to that of a high intensity workout. This reduction in oxygen leads to an increase in anabolic hormones, cellular swelling, and larger type II muscle fiber recruitment. Muscle tissue, blood vessels, and bones use anabolic hormones to facilitate repair, hypertrophy and increase strength. Muscle fatigue during BFR training stimulates the brain to release growth hormones which will circulate through the bloodstream, targeting anabolic receptors on all muscles that were used. This creates a “systemic response” and so BFR training will have a positive effect on all muscles in the area, not just those muscles below the level of occlusion. These hormones have a protective role for tendons and muscle collagen structures as it increases collagen synthesis. This makes BFR a great tool for recovery in athletes. For safety purposes, it’s important to understand we’re not cutting off blood flow all together for extended periods of time, as this would be dangerous.
Typically normal hypertrophy and strength gains are seen at lifting loads greater than 60% of a person’s 1 repetition max. BFR training hypertrophy and strength gains are seen at loads 20-30% of 1 repetition max. In other words, half the weight with similar results! With BFR training we are also able to see strength and hypertrophy gains in as little as 4 weeks, whereas normally it would take 8-12 weeks.
Would you benefit from BFR training? Although we do not recommend replacing high load resistance training with blood flow restriction training, it can be used in the rehab setting to increase muscle strength and size when a person is unable to lift heavier weights. For example, after most surgeries there is a period in time when a patient is restricted from using heavier loads and low load exercises are not enough to stimulate muscle hypertrophy. Studies have also shown that BFR training increases sprint speeds and muscular power.
Although BFR training is very safe under a physical therapist’s supervision, it is important to take precautionary measures. Those with a history of vascular compromise, history/risk of DVT, pregnancy, and varicose veins should not try BFR training.