Is Blood Flow Restriction Training Legit?

At first blood flow restriction training looks like it’s straight out of the bro science training handbook.

You’re saying we are going to strap tourniquets to our limbs, cut off most of the blood flow from said limb, and then train with super light resistance and all of this combined is going to make us jacked?


Surprisingly though, blood flow restriction training has a solid amount of research backing it. Even more surprisingly, blood flow restriction training could create a training stimulus comparable to training with heavy loads, all why using light to barely any resistance.

So, while this lands relatively high on the crazier looking ways to train in the gym, this could be a style of training you want to implement in your future programing. Especially if you’re the type of person that likes building muscle. Here’s the basics you need to know about blood flow restriction training.

What is Blood Flow Restriction Training?

Blood flow restriction training is exactly what it sounds like. The idea is to use either bands, specially designed tourniquets, or even pressure cuffs to restrict the blood flow of a limb during training. However, we are not just going full tourniquet mode and completely cutting off all blood flow.

The cuffs are attached distally (closer to the body) on the intended limb at a pressure which while restricting venous return of blood (veins: return blood to the heart to be oxygenated), still allows for arterial inflow of blood (arteries: bring blood to your limbs to transport oxygen). Broken down to basics, blood can enter your muscle, but it can’t leave while utilizing blood flow restriction.

The goal of blood flow restriction training is to use the cuffs to mimic the hypoxic environment that would be created in your limb under high intensity exercise, without having to utilize high intensity exercise…

Why Does this Work?

BFR Training works for a variety of reasons. The main idea you want to remember is that restricting venous return of blood creates an environment in our muscle that is more conducive to muscle growth, despite lower training loads.

These are some of the prime effects of training with blood flow restriction:

Increased Metabolic Stress: Metabolic Stress is a physiological process that can occur in response to exercise. Made simple, metabolic stress involves the accumulation of metabolites (refers to any intermediate or end products of metabolism), and in turn this accumulation of metabolites influences more physiological process down the line like hormone release, hypoxia, and cell swelling. Notably Metabolic stress is one of the 3 “key mechanisms” of hypertrophy (mechanical tension, muscular damage, metabolic stress). Training with BFR generates similar levels of metabolic stress with low training loads, compared to higher training loads without BFR.

Increased Motor Unit Recruitment: “Motor units” are a single motor neuron and all of the muscle fibers that neuron activates. By increasing motor unit recruitment we are effectively increasing the number of muscle fibers being activated, which means we are increasing the number of fibers we are training. BFR training with low loads increases motor unit recruitment compared to low load training with BFR, and increases motor recruitment to a comparable level of higher load training without BFR.

Cellular Swelling: When you hear bodybuilders talking about “the pump” cellular swelling is what they are referring to. Increased blood flow and intracellular hydration causes your muscle fibers to swell and this is a good thing when it comes to building muscle. Similar to metabolic stress, cellular swelling is beneficial for hypertrophy adaptations which is why a lot of bodybuilding workouts are based around not just training, but training specifically with developing a pump in mind. It should be no surprise that because we are allowing blood flow into the muscle but not back out of the muscle that BFR training results in significantly increased cellular swelling.

Increased Growth Hormone Release: First, resistance training in general will result in increased growth hormone release. Second, growth hormone release does not automatically insinuate muscle growth. That being said it is part of the muscle building process and it’s release is helpful in the recovery process of muscles. Additionally, BFR results in a notable increase in growth hormone release.

This is not everything there is to know about how BFR training effects muscle environment, but these are among the more notable results of BFR training.

Practical Application of BFR Training:

-For Hypertrophy: The practical application of BFR training for hypertrophy/bodybuilding purposes should be fairly straight forward. We can force similar training stimuli to if we had just used heavy training loads, all why using extremely light loads. This makes BFR relatively easy to recover from, allowing you to train it more frequently than you may be able to otherwise with heavier training.

-For Rehab: Something that may not be immediately obvious, is that while BFR training definitely sounds like a gym bros best dream, there is also a rehab application for BFR training. Because training load can be kept so light, injured individuals could still be kept on an effective training routine using BFR training. Whereas an injured individual would otherwise be spinning their wheels with light training loads, BFR training could provide them a higher level of training stimulus in lieu of being able to train with heavy loads.

Is Blood Flow Restriction Training Dangerous?

Individuals notably become wary when they hear about the idea of strapping a tourniquet to their arm or leg…understandable…

However, despite initial appearances BFR training has shown to be a safe training protocol to use.

For starters you are not completely cutting off blood flow using BFR training, only venous return of blood. Secondly, even if you were to accidently completely cut off blood flow, a tourniquet can be applied to a limb for a little over an hour with no long term side effects (NOT THAT YOU SHOULD GO DO THIS).

Additionally, people will fear using BFR training will increase their risk for a blood clot. Fortunately this is another topic that has been well studied and BFR will NOT increase your risk of developing a blood clot.

Matt Molloy

Matt Molloy

I'm a graduate the University of Pittsburgh with a major in Exercise Science. I’m a local guy (North Penn) and athletics has dominated my life. I've led teams in basketball, baseball, soccer, golf and my passion, long distance running. I've been strength training for 6 years with a focus in power-lifting but have recently stretched to strongman since joining the pride here at the Den. When I’m not in the gym I enjoy, spending time with my friends, music, and relaxing and playing some video games.