What is Blood Flow Restriction Training and how does it work?
Blood Flow Restriction training (BFR) is when circulation to an isolated muscle group is restricted forcing more blood to stay in the targeted muscle. This is done by using an occlusion band, knee wrap, or other thick cloth and tightly wrapping at the muscle origin (closest to body) point (Biceps for example you would wrap where the bicep meets the delt and wrap around and under the armpit). This should be tight but not to the point where circulation is completely stopped, shoot for a 7/10 tightness. Once restricted, work the targeted muscle group through a series of higher rep exercises at a 1RM of roughly 20-30%. Example: if you can curl 100 pounds once then with BFR you would curl 30lbs for 15+ reps.
There’s the What, so now the How?
BFR works by decreasing the amount of oxygen allowed to get into the muscle cell. This means a MUCH slower breakdown of lactic acid (what causes the “burning” we feel during an exercise). This alone does not cause much hypertrophy but does cause a chain reaction that does. When the muscle has increasing lactic acid (which rapidly breaks down to lactate, the real hero) metabolites (nutrients in the body) rush in and build up in the cells. The cells can only hold so much so are forced to either burst or become larger, either one causing an adaptation to take place telling the body to increase muscle fibers in the area to be able to handle this stress/build up in the future. The other condition BFR causes, due to the low oxygen supply, is the recruitment of other muscle fibers such as fast-twitch. The more muscle fibers recruited the greater the micro-tears which leads to the maximum amount of muscle recovery and growth. The reason those other fibers are recruited is due to the Krebs cycle not being able to replenish the cells with new ATP, so the body searches for any fibers left in the area it can use that still have some ATP left. It’s like being in the heat of an airsoft battle and you run out of BB’s so you shout to your closest team mate to see if they have an extra mag (I like airsoft analogies, sue me).
Great, now we know how to do it, but why would we want to?
The short answer? The more “damage” we cause to a muscle the more of a need the body sees to force that muscle to grow (increases muscle fibers in the area). This means the more muscle fibers in an area the larger and stronger the muscle becomes. Now this type of training isn’t for everyone and is just another tool at our disposal. As a coach, I only use BFR training on clients when they are rehabbing an injury, potential injury, or simply on a deload but still need to force progression. It can cause a lot of similar benefits to regular weight training but with less risk for injury.
So if you just HAVE to have bigger biceps and nothing (no one has patience anymore) is working, try ending your normal workout with 4 sets of 20 reps BFR style. Then talk to me about pain.
Sources
BFR %’s and recruitment
https://www.sciencedirect.com/science/article/pii/S0306987711005287
BFR metabolic build up
https://www.ncbi.nlm.nih.gov/pubmed/23338987
BFR hypertrophy