Blood Flow Restriction (BFR) training is a muscle building technique that has quite a bit of science backing it. So what is BFR and why should you use it?
BFR is a technique of training that incorporates using a tourniquet to occlude blood flow away from the muscle, inducing different muscle building responses. The catch is that you can induce muscle building, while using approximately 40% of your 1 Rep Max (1RM).
At first glance, this seems like a gimmick. But truth be told, it actually makes quite a bit of sense. As researchers have eluded in previous studies, muscle growth with light weight is quite possible. Only, you're required to approach failure. This makes sense since in order to drive a muscle growth adaptation, you need to provide it with a stimulus to do so.
Light weight is light because you've adapted to it. By adapting, you're stronger and more resiliant. Doesn't it then make sense that if you don't take sets close to failure that you won't stimulate the muscle to grow? Essentially, if there isn't enough stress on the muscle, the muscle won't grow.
Now with light weight, approaching failure, you may need to do an insane amount of reps. Chances are, with 40% you'll need 30-50 reps, maybe more. BFR simply expedites this process, making failure occur much sooner, plus you might get some extra benefit from the BFR technique itself.
BFR creates a ton of metabolic stress, potential stretching of the muscle cell membrane (sarcoplasmic hypertrophy) to allow for more content within the muscle and of course, allows for failure with light weight to occur much faster, potentially stimulating growth.
The Science Of Blood Flow Restriction
BFR training incorporates the use of a tourniquet, placed on your limbs, to occlude or restrict blood flow. Although not all blood flow is restricted. The use of the tourniquet is to specifically restrict venous return or the blood leaving the muscle, returning to the heart.
Normally, when un-restricted, blood leaving the muscle returns to the heart, bringing with it, bi-products from muscle contraction such as carbon dioxide, lactate and hydrogen ions. When venous return is restricted, blood, along with these bi-products pool in the muscle. It is thought that by doing so, this leads to activation of the bigger, fast twitch muscle fibers. Something that typically occurs when using much heavier weight. This in turn, increases the likelihood of increasing muscle size.
Further, since the blood is pooling in the muscle, along with metabolic byproducts of muscle contraction, this results in fatigue onset occurring much faster, while also stretching the muscle cell walls (since the blood is pooling in the muscle).
The use of a tourniquet essentially mimics the effects of heavier weight, taken close to failure, without the other mechanical stress and impact on joints that heavier weight provides.
By using blood flow restriction training, you can receive similar muscle building benefits as using heavy loads, but without placing a ton of stress on your body.
Why Use Blood Flow Restriction?
You can receive a similar benefit to using heavy weight.
While using heavy weight is likely necessary for a number of different adaptations, doing so can put your muscle, joints and nervous system under a lot of stress. By using blood flow restriction training, you can receive similar muscle building benefits as using heavy loads, but without placing a ton of stress on your body.
Using blood flow restriction is great for times when you are tired or just plain worn out from your heavy weight sessions.
You can do less work than you would at the same intensity, without a tourniquet.
If you use a relatively lighter weight (40% of 1 RM), you'll need to go to muscular failure to produce an adaptation response. The same goes for BFR training. However, you'll reach this failure threshold much sooner with BFR.
A study by Farup et al., in 2015 revealed that a BFR group received the same benefit using 40% of 1 RM loads, but did so with significantly less repetitions than a group that did not use a tourniquet with the same load. So essentially, you're getting the same benefit of training to failure with light weight but just expediting the process.
It can be used when coming off an injury.
Use of BFR is also a great idea when recovering from an injury. Since you can use significantly lighter weight, you can receive muscle building responses, but not put your muscle and joints under a lot of mechanical stress.
Further, there is even speak of using BFR without lifting for injury healing and prevention of muscle atrophy. While this theory is still just that, many practitioners believe that simply wrapping the limb as you would during BFR, during recovery from an injury may prevent atrophy or muscle degradation due to disuse. It's thought that wrapping alone may provide some growth stimulus to prevent the decline of muscle when injured. Very interesting stuff.
How To Perform Blood Flow Restriction
You'll need some sort of tourniquet to perform BFR. You'll also want to make sure it's elastic so that your muscle can expand and contract. The point is to occlude blood flow, not restrict range of motion. For legs, you'll need a bit larger of a wrap, yet not one that impedes movement. If you want to use BFR for legs, I suggest this product or using a thin, elastic knee wrap.
When performing BFR, you'll want to place the tourniquet on the proximal portion of the limb. This means above the muscle, while also close to the torso. For example, if you are planning on working your biceps, you'll place the tourniquet above the bicep, and below the deltoid. Right in the crease where the two connect.
For lower body, a majority of experts suggest that you should place the tourniquet above the quadricep, near the groin. This also includes when training for calves.Essentially, you'll place the wrap just in the crease of your butt cheek and hamstring.
However, in personal experience, this is difficult especially if you have large thighs and a small tourniquet.
For upper legs, consider using an elastic knee wrap or click the link above. For calves, consider placing the tourniquet underneath the knee, above the calf. This however, is not necessary as you can simply use the wrap higher up on the leg and get a similar benefit.
Remember, the goal is to occlude venous return, not completely restrict blood flow. When wrapping, use a wrapping pressure at a 7 on a scale of 1 to 10.
If your limb falls asleep before you even start exercising, you've wrapped too tightly. If your limb doesn't even feel pumped up after the first set, you've wrapped too loosely.
When using BFR, you'll need to approach muscular failure. Further, you'll want to use a maximum intensity of 40% of 1 RM. If you can bicep curl 100 lbs. for 1, you should use 40 pounds.
Additionally, you'll want to have minimal rest between sets. A good template is as follows:
Important Considerations For Blood Flow Restriction
A majority of experts agree that blood flow restriction training is in fact safe when performed correctly.
Ensure that you have not completely occluded blood flow and unwrap your limbs immediately after completing all BFR sets. A good rule of thumb is to unwrap and then re-wrap each time you switch exercises.
Finally, BFR should be used as a supplemental tool. It shouldn't be used to replace other types of training, unless an injury or something similar prevents doing so. Research indicates that BFR can be "as good" as other types of training, not superior. I suggest incorporating BFR during times in which you are fatigued, and simply just every once in a while for each muscle group to provide a novel stimulus.