Blood flow restriction (BFR) training is a therapeutic technique that restricts blood flow to your arms or legs during exercise to help with injury rehabilitation, tendinitis, post-surgery, strength maintenance during recovery, and even performance optimization for athletes. When I was in rehabilitation a, my physical therapist used BFR training as part of my recovery process. This was the first time I had used this recovery tool and it was unlike any other technique I had tried.
The best way to describe it is this: Imagine having a tourniquet-like cuff wrapped tightly around each of your legs, making simple exercises that much more difficult. For example, the first time I tried BFR training, I was doing bodyweight squats and my quads were much more sore than I expected the next day. It was reminiscent of the soreness you feel a day or two after a day of intense squatting.
After a few rounds of BFR training I noticed that my legs were stronger and recovered. I was interested in learning more about the method and how it benefits people with different goals, as well as whether there are any risk factors associated with it. I spoke with Nicholas Rolnick, physical therapist and owner of The Human Performance Mechanic in New York, about the benefits of BFR training and how it helps almost everyone (regardless of age and background) recover better and perform better in the gym. Read on to learn more about this popular rehabilitation technique.
How does blood flow restriction training work?
To perform BFR training, a specially designed Velcro cuff is placed on your arm or leg (or both). To determine your personalized pressure, the cuff is connected to a hand-held machine that inflates the cuff to the point where blood flow to the limb is blocked. This is known as arterial or limb occlusion pressure.
Once the blood flow is restricted and the cuffs are detached from the handheld device, you can perform exercises with little or no weight and still produce a “pump” similar to when you lift heavy or perform high repetitions.
The purpose of blood flow restriction is to provide the same benefits as lifting heavy weights, such as increasing muscle mass and strength, through low-intensity training. As a result of this technique, your muscles work harder to contract and you will tire sooner than if your blood flow were not restricted. This is a good thing because it means you get the same benefits as a hard workout – but in a less intense way. Therefore, you are less likely to injure yourself while safely building strength.
During BFR training, Rolnick explains, you typically perform resistance exercises using four sets for each movement. “For example, you’d do 30 reps in the first set, then three sets of 15 reps with 30 to 60 seconds of rest between sets,” he said. “BFR is usually applied continuously – meaning the applied pressure is only released when the last repetition of the fourth set is completed.”
This was the same format I followed when using BFR training with resistance band exercises. Band walks, bridges and heel lifts that would normally take twice as many reps to make me feel tired, rather I felt challenged while my blood flow was restricted.
Although the research on BFR training and its effects on endurance training isn’t as conclusive on its resistance training benefits, if you plan to use BFR while doing aerobics, Rolnick said there are a few ways to do it. “Typically for aerobic exercise, it’s done for 10 to 15 minutes 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’re interested in measuring your VO2 max, there are several ways to determine that number, such as a treadmill test or a walk/run test administered by your doctor.
Benefits of blood flow restriction training
Besides gaining muscle mass and getting stronger, there are many benefits you can get from BFR training.
“Other potential benefits include pain relief, [improved] cardiovascular capacity and even increased tendon and bone strength,” Rolnick said.
There are other modalities of physical therapy such as instrumental soft tissue mobilization, kinesio taping or ultrasound that are used in rehabilitation clinics. However, what makes BFR training unique is that there are many studies that continuously confirm how effective it is in different groups of people.
“If an exerciser effectively incorporates blood flow restriction into their routine, they can be guaranteed to create a positive change in their body,” promises Rolnick.
How long should you do BFR training?
BFR training aims to prevent muscle atrophy (loss of muscle mass) and promote hypertrophy (gain of muscle mass), even when you are unable to lift heavy. “In a rehab setting, BFR is typically administered for six to eight weeks before transitioning to higher-load strength training for those who must lift heavy weights due to their lifestyle or sport,” explains Rolnick. According to research, this treatment has been applied to at-risk populations for a longer period of time ranging from two to six months. In addition, recent studies conducted on patients with chronic kidney disease have shown that it is safe to do BFR training for up to six months under the supervision of an expert.
It is unclear whether the same training prescription would apply to unsupervised environments, but a BFR resistance and aerobic program of eight to 12 weeks is generally recommended. Regardless of the approach you choose, conducting a thorough screening process is critical to reducing the risk of adverse events.
Who should or shouldn’t be doing BFR training?
BFR training is a universal tool that can help almost anyone. People who have trouble carrying or lifting heavy weights due to injury, surgery, other health problems, as well as joint or muscle pain are good candidates for BFR training. Rolnick recommends an examination by a BFR-trained provider who can offer a thorough assessment of your medical history, physical activity history, and other factors that may be relevant to determining whether you’re a good candidate.
As with any treatment, there may be certain risks associated with BFR training. There is a small risk of muscle damage or an exaggerated cardiovascular response, such as high blood pressure. Rolnick said some risks can be prevented by modifying an individual’s BFR training prescription as needed and making sure the provider providing the BFR training is qualified.
For example, muscle damage can occur during strenuous BFR training, such as performing multiple sets of exercises until it feels like it’s hard to finish. “BFR-trained providers understand that this risk is easily managed by avoiding exercise to failure and/or temporarily reducing the training load to allow the body to adapt and become more resilient,” explains Rolnick.
BFR training increases blood pressure during exercise, which is expected. However, for people with certain medical conditions, a better strategy might include applying less pressure, reducing pressure during rest periods, and avoiding multi-joint exercises.
Rolnick said, “This response may be exacerbated in those with certain medical conditions and warrants consideration of other training approaches and/or modification of the BFR training prescription.” He suggests monitoring your blood pressure levels during the first few sessions to make sure your blood pressure doesn’t go above critical levels.
There have previously been safety concerns about BFR training and blood clots. But Rolnick said there is not enough evidence to show that BFR training increases the risk of blood clots, and instead may reduce the risk because of the way the body responds to the temporary restriction and release during exercise.
Can BFR be done at home?
Similar to other forms of physical therapy, such as using a TENS machine, you can safely do BFR training at home. But it’s important to first go through a screening process with a trained BFR provider to learn how to get the most out of your sessions.
“When BFR is done correctly, it’s uncomfortable. So if you’re doing BFR and you’re not uncomfortable, it’s probably not doing anything,” Rolnick said. He explained that discomfort is the first signal that a beneficial muscle-building stimulus is occurring. “To promote adaptation, we must push our physical and mental limits beyond that discomfort to expand our capacities and promote the benefits of muscle mass, strength and cardiovascular capacity.”
If someone uses BFR training for pain relief, it can be expected that they will experience discomfort such as pressure and some numbness in the area during resistance training. Rolnick said that BFR training has a powerful effect on pain-relieving responses, and that you should aim to achieve discomfort that is challenging but tolerable in order to maximize the therapeutic effect. However, excessive pressure or improper use of BFR strips can lead to burning or stabbing pain. This is something to watch out for as it can be a sign of nerve damage.
Take it away
BFR training is a useful option to keep in mind if you ever need to heal or strengthen after an injury. From personal experience, it definitely takes some getting used to because it’s not every day you do squats with partially cut off blood flow. 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 BFR-trained provider. That way you can get a proper assessment and get the most out of this type of therapy.
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health care professional with any questions you may have about your health condition or health goals.