Flow restriction training makes you stronger without the heavy weights

Flow-restriction training is a technique that restricts blood flow in your arms and/or legs during exercise to help rehabilitate injuries, tendinitis, and post-operative surgery (such as knee surgery), maintain strength during recovery, and even improve performance for competitive athletes. When I was rehabilitating an injury while training for my last race, my physical therapist used BFR training as part of my tendinitis recovery process. This was a tool I never used during my other rehab sessions.

The best way to describe it is: Imagine having a tourniquet or blood pressure-like cuff wrapped around each of your legs, making simple exercises (or so it seems) more difficult. The first time I tried this technique, my quads were a lot sadder than I expected the next day. The kind of pain I’ve been feeling I usually feel a day or two after a day of heavy volume squats.

After several rounds of BFR training, I noticed that the pain after training wasn’t too bad and my legs felt stronger and recovered more. I was convinced the BFR training was on to something and was curious to learn more about this method. I was interested in better understanding how BFR training works, how it benefits people with different goals, as well as the associated risk factors. I spoke to Nicholas Rolnik, a physical therapist and owner of Human Performance Mechanic in New York, about the benefits of BFR training and how it works to help almost anyone (regardless of age and background) recover better and perform better in the gym. Read on to learn more about a popular rehabilitation technique.

How does blood flow restriction training work?

To perform BFR training, a specially designed pressure cuff is placed on either your arm or your leg (or both). To determine your personal pressure, the cuff is connected to a hand-held device that inflates the cuff to the point where blood flow to the limb is blocked. This is known as arterial or extremity occlusive pressure.

Once your blood flow is restricted and the handcuffs are separated from the portable device, you can perform exercises with little or no weight and still generate a “pump” similar to what you would when you lift weights or perform multiple reps.

The purpose of restricting blood flow is to provide the same benefits as lifting heavy weights, such as gaining muscle mass and strength, through low-intensity training. As a result of this technique, your muscles work harder to contract and will tire sooner than if blood flow had not been restricted. This is a good thing because it means that you reap the same benefits as hard exercise – but in a way that is less intense. Therefore, you are less likely to get injured while safely building your strength.

Rolnik explains that during BFR training, you typically do resistance exercises using four sets of each movement. “For example, you can do 30 repetitions in the first set followed by three sets of 15 repetitions with a 30- to 60-second rest between sets,” he said. “The BFR is usually applied continuously – which means that the applied pressure is only released once the last repetition of the fourth set is done.”

This was the same look I did when I used BFR training with resistance exercises. Band walks, bridges, and heel lifts that would normally take double reps until I was exhausted, felt challenged sooner while blood flow was restricted.

Blood flow restriction is trained by restricting blood flow in your arms or legs using a tourniquet or a blood pressure-like cuff wrapped around each end of your limb.

Gisele Castro Sloboda / CNET

Although the research on BFR training and its effects on endurance training isn’t conclusive as to its benefits with resistance training, if you’re planning to use BFR while exercising, Rolnik said there are several ways to do it. “Typically 10 to 15 minutes of aerobic exercise is done at a low intensity or less than 50% of your VO2max,” he explains. VO2max refers to the maximum amount of oxygen you use during intense exercise. If you are interested in measuring your VO2 max, there are several ways to find out this number, such as a treadmill test or a walking/running test done by your doctor.

Benefits of blood flow restriction training

Besides gaining muscle mass and gaining strength, there are a lot of benefits that you can reap from BFR training.

Other potential benefits include pain relief, [improved] “Cardiovascular capacity and even increased tendon and bone strength,” Rolnik said.

There are other methods of physical therapy such as instrument-assisted soft tissue mobilization, kinematic planning or ultrasound used in rehabilitation clinics. However, what makes BFR training unique is that there are many studies that consistently support its effectiveness in a variety of people.

“If an exerciser effectively incorporates blood flow restriction into their routine, they can be guaranteed to bring about a positive change in their bodies,” promises Rolnick.

How Long Should You Practice BFR Training?

BFR training aims to prevent muscle atrophy (loss of muscle mass) and encourage hypertrophy (increased muscle mass), even when you are not able to lift weights. “In the rehab setting, BFR is typically applied for six to eight weeks before transitioning to heavy-duty strength training for those who need to lift weights for their lifestyle or sport,” explains Rolnik. According to research, this remedy has been applied to Populations at risk for extended periods of time from two to six months. Additionally, recent studies in patients with chronic kidney disease have shown that it is safe to do BFR training for up to six months under professional supervision.

It’s unclear whether the same training prescription would apply to unsupervised settings, but in general, an eight to 12 week BFR resistance and resistance exercise program is recommended. No matter which method you choose to go with, a thorough screening process is key to reducing the risk of adverse events.

Who Should or Shouldn’t BFR Training?

BFR training is a universal tool that can help anyone. People who have problems carrying or lifting heavier weights due to an injury, surgery, or other medical problems, as well as joint or muscle pain are good candidates for BFR training. Rolnick recommends undergoing an examination by a provider trained in BFR who can provide a detailed assessment of your medical history, physical activity history, and other factors that may be relevant to determine if you are a good candidate.

As with any treatment, there may be some risks involved with BFR training. There is little risk of muscle damage, or of an increased cardiovascular response, such as from high blood pressure. Rolnik said some of the risks can be prevented by adjusting the individual’s BFR training prescription as necessary and ensuring that the provider performing the BFR training is qualified.

For example, muscle damage can occur during hard BFR training, such as doing multiple sets of exercises until they feel hard to complete. “Providers trained in BFR understand that this risk can be easily managed by avoiding exercise until failure and/or temporarily reducing training loads to allow the body to adapt and become more flexible,” explains Rolnik.

BFR training increases blood pressure during exercise, which is to be expected. However, for people with certain medical problems, a better strategy can include using less pressure, reducing stress during rest periods and avoiding multi-joint exercises.

“This response may be exacerbated in people with certain medical conditions and necessitates consideration of other training approaches and/or modification of the BFR training prescription,” Rolnik said. It is suggested that you keep track of your blood pressure levels during the first two sessions to ensure your blood pressure does not exceed critical values.

Previously, there were safety concerns about training with BFRs and anticoagulants. But Rolnik said there isn’t enough evidence to show that BFR training increases the risk of blood clots, and may instead reduce the risk because of how the body responds to temporary restriction and release during exercise.

Can BFR be done at home?

smart handcuffs case

Smart Cuffs is one brand that you can buy for home use.

Gisele Castro Sloboda / CNET

Similar to other forms of physical therapy, such as using a percutaneous electrical nerve stimulation machine, you can perform BFR training safely at home. But it is important to first undergo a check-up with a trained BFR provider so that you learn how to get the most out of your sessions.

“When the BFR is done correctly, it’s uncomfortable. So, if you’re doing a BFR and not experiencing discomfort, you probably shouldn’t be doing much of anything,” said Rolnik. He explained that discomfort is the first sign of a beneficial muscle-building stimulus. “To promote adaptation, we need to push our physical and mental limits beyond this discomfort to expand our capacity and promote benefits in muscle mass, strength and cardiovascular capacity.”

If someone is using BFR training for pain relief purposes, discomfort such as pressure and some numbness at the site will be expected during resistance training sessions. Rolnik said that BFR training has a strong impact on pain-relieving responses and should aim to achieve discomfort that is challenging but tolerable, to maximize the therapeutic effect. However, excessive pressure or improper use of BFR tapes can lead to burning or stabbing pain. This is something to look out for as it can be signs of nerve damage.


BFR training is a helpful option to consider if you ever need to recover or recover after an injury. From personal experience, it sure takes some getting used to because it’s not every day you do squats with your blood flow partially cut off. The good thing is that BFR training has been shown to be safe for most individuals, but if you have reservations, consult your physical therapist or provider trained in BFR. This way you can get the proper evaluation and make the most of this type of treatment.

The information in this article is for educational and informational purposes only and is not intended to provide medical or health advice. Always consult a physician or other qualified healthcare provider with any questions you may have about a medical condition or health goals.

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