Blood flow restriction training (BFR) is a therapy that restricts blood flow to your arms or legs during exercise, helping with injury rehabilitation, tendinitis, post-surgery, maintaining strength during recovery, and even optimizing performance for competitive athletes. When I rehab a, my physical therapist used BFR training as part of my recovery process. This was my first time using this tool to recover and it was different from other methods I tried.
The best way to describe it is this: Imagine a tourniquet-like cuff wrapped tightly around each leg, making simple exercises more difficult. For example, the first time I tried a BFR workout, I did bodyweight squats and my quads were much tighter than I expected the next day. It was reminiscent of the soreness you feel a day or two after a day or two of heavy volume squats.
After a few rounds of BFR training, I felt my legs feel stronger and more healed. 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 physical therapist and owner of Human Performance Mechanics in New York, Nicholas Rolnick, about the benefits of BFR training and how it works to help almost anyone (regardless of age or 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 the BFR exercise, a specially designed pressure Velcro cuff is placed on either your arm or leg (or both). To determine your personalized pressure, the cuff is attached to a hand-held device that inflates the cuff to the point where blood flow around it is blocked. This is known as arterial or limb occlusion pressure.
Once the blood flow is restricted and the cuffs are removed 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 do high repetitions.
The goal of blood flow restriction is to provide the same benefits as lifting heavy weights, such as gaining muscle mass and strength through low-intensity exercise. As a result of this technique, your muscles work harder to contract and you tire more quickly because blood flow is not restricted. That’s a good thing, because it means you’ll get the same benefits as an intense workout, but at a much lower intensity. Therefore, you are less likely to get injured while building strength safely.
During BFR training, Rolnick explains, you typically do resistance exercises using four sets for each movement. “For example, you’d do 30 reps on the first set, then three sets of 15 reps with 30 to 60 seconds of rest between sets,” he says. “BFR is usually applied continuously – meaning the applied pressure is released only after the last repetition of the fourth set is completed.”
This was the same format I followed when using BFR training with resistance band exercises. Group walks, bridges, and heel lifts, which usually require two repetitions before I feel fatigued, become difficult more quickly when my blood flow is restricted.
Although BFR training and its effects on endurance training aren’t as definitive as the benefits of resistance training, if you’re planning to use BFR while doing aerobics, Rolnick says there are a few ways to do it. “Typically for aerobic exercise, this is done at a low intensity or less than 50% of VO2max for 10 to 15 minutes,” 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 determine this number, such as a treadmill test or a walk/run test performed by your doctor.
Benefits of blood flow restriction training
Aside from gaining muscle mass and getting stronger, there are many benefits you can get from BFR training.
“Other potential benefits include pain relief, [improved] it increases cardiovascular capacity and even tendon and bone strength,” Rolnick said.
There are other physical therapies such as soft tissue mobilization, kinesiotherapy, or ultrasound that are used in rehabilitation clinics. However, what makes BFR training unique is that there are many studies that consistently support how effective it is in different groups of people.
“If an exerciser effectively incorporates blood flow restriction into their regimen, they can be guaranteed to make a positive change in their body,” promises Rolnik.
How long should you continue BFR training?
BFR training aims to prevent muscle atrophy (loss of muscle mass) and promote hypertrophy (put on muscle mass) even when you are unable to lift weights. “In a rehab setting, BFR is typically practiced for six to eight weeks before moving on to heavier weight training for lifestyle or sport,” explains Rolnick. According to research, this treatment has been applied populations at risk over long periods of two to six months. In addition, recent studies in patients with chronic kidney disease have shown that up to six months of BFR training under the supervision of a specialist is safe.
It is unclear whether the same exercise prescription would apply to uncontrolled conditions, but generally an eight to 12 week BFR resistance and aerobic program is recommended. Regardless of the approach you choose, a thorough screening process is key to reducing the risk of adverse events.
Who should or should not do BFR training?
BFR training is a universal tool that can help almost anyone. People who have trouble carrying or lifting heavier weights due to injury, surgery, other medical problems, and joint or muscle pain are good candidates for BFR training. Rolnick recommends getting tested by a provider trained in BFR, who can offer a detailed evaluation of your medical history, physical activity history, and other factors that may be a good fit to determine if you’re a good candidate for it.
As with any treatment, BFR training can have some risks. There is little risk of an extreme cardiovascular reaction such as muscle damage or high blood pressure. Some risks can be avoided by modifying an individual’s BFR training prescription as necessary and making sure the provider performing the BFR training is qualified, Rolnick said.
For example, muscle damage can occur during heavy BFR training, such as doing multiple sets of an exercise until you struggle to finish. “BFR-trained providers understand that this risk can be easily managed by avoiding training to failure and/or temporarily reducing training loads to allow the body to adapt and become more resilient,” explains Rolnick.
BFR exercise increases blood pressure during exercise, which is expected. However, a better strategy for people with certain medical conditions may be to apply less pressure, reduce pressure during rest periods, and avoid multi-joint exercises.
“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,” Rolnick said. He suggests monitoring blood pressure levels during the first few sessions to ensure your blood pressure does not exceed critical values.
There have previously been safety concerns regarding BFR training and blood clotting. But Rolnick said there isn’t enough evidence to show that BFR training increases the risk of blood clots, and instead it may reduce the risk based on how the body responds to 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 practice BFR at home. But first, it’s important to go through the screening process with a trained BFR provider so you learn how to get the most out of your sessions.
“When BFR is done right, it’s uncomfortable. So if you’re doing BFR and you’re not feeling uncomfortable, it’s probably not doing anything,” Rolnick said. He explained that anxiety is the first signal that a beneficial muscle-building stimulus is occurring. “We need to push our physical and mental limits beyond this concern to expand our capacity to promote adaptation and promote benefits in terms of muscle mass, strength and cardiovascular capacity.”
If someone is using BFR training for pain relief purposes, discomfort such as pressure in the area and some numbness during resistance training is to be expected. Rolnick says that BFR training has a powerful effect on pain-relieving responses, and that you aim to achieve a difficult but tolerable level of discomfort to maximize the therapeutic effect. However, too much pressure or improper use of BFR belts can cause burning or stabbing pain. This is something to watch out for as it can be a sign of nerve damage.
BFR training is a useful option to keep in mind when you need to recover or strengthen after an injury. In my personal experience, it definitely takes some getting used to because it’s not every day you squat with partial blood flow cut off. The good news is that BFR training has been shown to be safe for most people, but if you have reservations, consult your physical therapist or BFR-trained provider. So you can get a proper assessment and get the most out of this type of therapy.
The information in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult your physician or other qualified health care provider with any questions you may have regarding a medical condition or health goals.