Like any other field in healthcare, physiotherapy is always developing new techniques and technologies for treating patients. An exciting new piece of technology that is finally entering the Canadian Physiotherapy industry is called Blood Flow Restriction (BFR), and it might just be the Holy Grail of rehab exercise. Despite recently becoming available to Physiotherapists in Canada, BFR has gained serious momentum in the US and around the world, particularly in the North American sports world.
What is Blood Flow Restriction?
The American College of Sports Medicine states that in order to build muscle strength and size, it’s necessary to lift greater than 70% of your 1-rep max (that maximum amount of weight you can lift for a single repetition). However, there are many cases in which it’s unfeasible or unsafe to be lifting that heavy. If you’ve just had your ACL replaced, for instance, it’s too fragile to begin squatting at such a weight, which is why Physiotherapists start you on lower resistance exercises for 6-8 weeks. While these exercises are safe, they don't build muscle effectively; this is where BFR comes in.
Blood flow restriction training involves the application of a pneumatic tourniquet to an exercising limb, inflating it to partially restrict the blood flow in that limb (primarily the blood returning to the heart). Training under these conditions produces significantly greater gains in muscle strength and size compared to light exercise alone, with benefits seen while training at only 20-30% of 1-rep max! These light exercises for patients coming off surgery are now much more effective.
How does it work?
Basically, light resistance exercise under BFR tricks the body into thinking it’s exercising at high intensity. The BFR unit keeps the blood in the exercising limb, creating an environment metabolically similar to that seen during high intensity exercise. A few biomechanical pathways appear to result in the gains seen with BFR (increased growth hormone, protein activation), as well as mechanisms that involve muscle stem cell activation, cellular swelling, and fast twitch muscle fibres. These mechanisms likely all work together to produce these benefits.
A great deal of research, including a recent meta-analysis in the British Journal of Sports Medicine, finds that BFR is more effective at building muscular strength than low-load resistance exercise alone. It also concludes that BFR is more tolerable for patients who find exercise painful. However, BFR is not as effective at increasing muscle mass and strength as traditional high intensity exercise.
BFR sounds like it could come with safety concerns, with blood clots as a specific risk that many people ask about. Plenty of research has been done to assess these risks, with a large number of participants of widely varying age groups, and the conclusions indicate there is a miniscule number of serious side-effects, and it poses no greater risk than traditional high intensity exercise. Read more about the safety of BFR here.
The increasing use of Blood Flow Restriction technology in the Canadian physiotherapy field is an exciting trend for physios and patients alike. This technology is starting to be used at Lifemark, with our West Kelowna and Garibaldi Highlands clinics implementing BFR in their rehab programs!