What is Blood Flow Restriction?
Blood flow restriction (BFR) exercise occurs with external pressure over the extremities. The applied pressure is sufficient to maintain flow through the arteries.¬† However, it decreases venous flow distal to the restricted site. The goal is to enable patients to make greater strength gains while lifting lighter loads.¬† This reduces the overall stress placed on the joints and muscles.
What is Blood Flow Restriction Training used for?
Normal strength and hypertrophy (increasing muscle size) are achieved with lifting resistance close to 70-80% of a one repetition maximal effort (1RM).¬† When a muscle or body part is injured, lifting at such a high level of resistance may be contraindicated.¬† BFR exercise allows one to achieve strength/hypertrophy gains with only 20-30% 1RM without stressing the injured areas. This potentially has a use for patients post-op surgery or injury.¬† Also, a recent study looked at BFR exercise in a patient with Parkinson‚Äôs disease and found they were able to improve their walking ability.
Is Blood Flow Restriction Safe?
Medical grade tourniquets have been used for a long time without adverse effects.¬† Think of surgeries where tourniquets are applied for long hours (ie., hip replacements, ACL reconstruction, etc).¬† Today‚Äôs medical grade tourniquets are able to dynamically accommodate the pressure to occlude blood flow but also maintain a safe level throughout an exercise.¬† A 2016 large systematic review looked at BFR exercise and found little to no research showing a higher risk than typical exercise at higher resistance loads.
However, one should not take a simple rubber band or strap and wrap it around a limb to occlude blood flow.¬† This strategy is not FDA approved and without proper training can increase the risk of bodily harm or injury.¬† Also, those with chronic medical conditions, a compromised cardiovascular system or other medical problems could be a contraindication to BFR.¬† Only a trained medical professional can help you decide if this intervention would be right for you.
Blood flow restriction is an intervention skilled physical therapists can utilize to help patients increase strength with a significant decrease in load on the joints and muscles.¬† Research so far has been quite promising for different injuries and populations especially for those recovering from injury or surgery.
Written by Dr. Mark Daitol, PT, DPT