What is Blood Flow Restriction (BFR) Training?
by Dr. Ashley O'Rourke PT, DPT, ATC, LAT
Blood Flow Restriction (BFR) training is a technique that combines low intensity exercise with blood flow occlusion that produces similar results to high intensity training. It has been used in the gym setting for some time but it is gaining popularity in clinical settings...
What is Blood Flow Restriction Training (BFR)?
Blood Flow Restriction (BFR) Training is a strategy that involves the use of cuffs (tourniquet) placed around the proximal (upper part of the) limb inflated during exercise to a specific pressure with the aim of maintaining arterial inflow while occluding venous return. When performing BFR for resistance training purposes, relatively light loads of around 20-30% of 1 RM (rep max) with high repetitions per set (15-30) and short rest intervals (30 seconds) between sets allow a person to increase strength without the stress/strain of heavy lifting. This is particularly beneficial following injury or surgery when strengthening is indicated for recovery, but heavy loads would be painful, contraindicated or place too much stress on the tissue. Resistance training with BFR has also been shown to increase post-exercise muscle protein synthesis and elevate growth hormone levels.
Because the outflow of blood is limited using the cuff, capillary blood that has a low oxygen content collects and there is an increase in protons and lactic acid. The same physiological adaptations to the muscle eg. release of hormones, hypoxia and cell swelling, will take place during the BFR training with low intensity exercise as would occur with high intensity exercise.
How is it performed?
A tourniquet is placed around the limb during exercise to restrict the blood flow from the working muscle. This causes a localized hypoxic environment, leading to faster muscle fatigue which results in a multitude of beneficial physiological adaptations. The "max" pressure is determined by finding at what pressure there is a "loss of pulse". The cuff is then set somewhere between 40-80% of that max pressure or "loss of pulse" pressure depending on the limb being worked. Exercises are performed while the cuff is inflated. The cuff is deflated during periods of rest between sets. See example protocol below:
Strengthening Protocol:
START WITH 1-2 EXERCISES
MAXIMUM OF 5-6 EXERCISES
FREQUENCY: 2 TO 3 TIMES PER WEEK WHEN BODY WEIGHT OR 15% TO 30% 1 RM TRAINING IS
SAFE
UPPER EXTREMITY: 40% - 50% Loss of Pulse
LOWER EXTREMITY: 60% - 80% Loss of Pulse
4 TOTAL SETS (30 SECOND BREAK BETWEEN EACH SET)
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