Blood Flow Restriction: Hacking Your Body’s Ability to Build Muscle And Strength

May 11, 2023
Blood Flow Restriction: Hacking Your Body’s Ability to Build Muscle And Strength

What if I told you that there was a method in which you could hack your body’s physiology and trick it into building muscle and getting stronger, all without lifting heavy weights? You could slow muscle wasting before and after surgery, recover faster, and also increase muscle size.

It seems like the start to a terrible infomercial right? One where you’re making “3 easy payments of just $19.99!” But the truth is that this is a very real phenomenon. Not only that, but the building body of research is showing that it’s a great option that works extremely well. Welcome to the wonderful world of blood flow restriction.

Before we dive into the mechanism of blood flow restriction (BFR), let’s talk about how the body naturally builds muscle and increases strength. Like all adaptations and changes within the body, strength is a response to a certain stimulus.

How Normal Muscle Growth Happens

Mechanical Stress:

This is when you stress a muscle to the point of failure. This is almost exclusively done with high loads (closer to one rep max) as well as with lower loads for high amounts of repetitions. These methods, used over a period of time, result in micro damage to the muscle cells, which signal to the body to increase muscle growth in that area to comply with the new regular increases in demand. This, of course, assumes that the nutrition and diet of the person have provided the proper building blocks for muscle. This mechanism is only viable if a given person is healthy enough to endure high load and/or high amounts of reps.

Metabolic Stress:

In the case of metabolic stress, the end result is the same in terms of the body causing an increase in muscle and strength. The difference is that instead of responding to mechanical stress of the muscle, it is responding to the chemical stress of the atmosphere that the muscle is in. When we use a muscle, those muscle cells utilize oxygen and other molecules in order to form contractions. As a result, waste molecules are produced, such as lactate (more commonly known as lactic acid). If there is a build-up of lactate, it creates a stressful environment for the muscle cells, which forces them to adapt, signaling an increase in muscle growth and strength. Therefore, with metabolic stress, you do not need to physically tax the muscle as much as you do with mechanical stress to achieve similar results in terms of strength and hypertrophy.

How Blood Flow Restriction Works

1: Allow Blood Flow In, Restrict Blood Flow Out

When using BFR, a cuff is placed on each limb being targeted. The cuffs are then inflated like a blood pressure cuff, which causes pressure against the arm or leg. The pressure is such that blood flow into the limb happens at a diminished rate, but blood flow back up the limb is at least partially or completely restricted. Exercises are then performed in high repetitions using lower loads in order to work the muscles below and directly above the cuff.

2: Blood and Metabolites Are Trapped Below the Cuff

As the muscles work, bi-products like lactic acid are trapped below the cuff and can not return to the rest of the body to be recycled. This creates an acidic, stressful environment that we talked about above, signaling to the brain that an adaptation must be made. That environment usually results in a classic “muscle burn” when exercising, and often results in what experienced lifters refer to as a “pump”, meaning that there is blood rushing to the targeted muscle.

3: Hormones Are Released Following the Workout

Following a session using BFR, the body releases hormones called IGF-1 and GH. These hormones are released in response to stress put on the muscle and signal for increased muscle growth and recovery.

“What BFR is able to do is essentially trick your body and brain into thinking that you are working much harder than you actually are

The metabolic stress created by BFR mimics the stress attained by lifting much higher loads. Therefore it is an excellent way to attain muscle and strength growth without having the same muscle damage or stress levels associated with heavier lifting. This becomes very useful in certain circumstances and with certain populations.

How Can BFR Training Benefit You?

Strength and Muscle Hypertrophy Are Good For Everybody

Largely speaking, increases in lean muscle mass have been shown to prevent everything from falls in the elderly to increased performance on the field. Increasing strength allows athletes to maximize power output and helps to properly stabilize joints when undergoing activity.

Avoiding Muscle Loss Pre and Post Surgery

An unfortunate part of undergoing surgery is the immobilization period and period of inactivity that often follows. This almost always leads to some form of muscle atrophy from disuse. This then requires weeks/months of rehab to not only gain strength back, but also return to equal levels of muscle mass (many people are still left with asymmetries even years later). BFR protocols allow for stress to the muscles without compromising the integrity of the surgery and putting the patient at risk. This is arguably the best application of this tool!

Recovery Protocols

BFR is not only used for strength and muscle gain, but for recovery too. By flooding a sore muscle group with blood, BFR has been shown in the most recent studies to decrease the amount of soreness post training and competition, and result in increased performance following a training bout.

Straight Up Gains

BFR allows for increased hypertrophy of muscle without the same stress, which makes it perfect as a finisher to any training session, without resulting in a high amount of post workout soreness.

*****Note: It is important to understand that lifting with heavier loads still has the best outcomes in terms of recovery, strength, and tendon function. BFR is best used as an adjunct to heavier lifting or to bridge the gap until a person is able to load heavier amounts of weight into their routine.


While BFR training may seem scary and extreme, it is one of the most rigorously studied interventions and has many safety protocols that allow practitioners to properly question and screen patients. The vast majority of studies have concluded that this form of training is extremely safe and effective, and even places less stress on the body than more typical forms of exercise, such as weight training and high intensity interval cardio training. Make sure that you are properly screened by your clinician before initiating this form of treatment and always provide the most accurate medical history that you can! If you have more questions about BFR, reach out to us at

Until next time - Brett Poniros DC, CSCS