Written by Kiel DiGiovanni | Co-founder
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
If you’ve been browsing Instagram or went to the gym over the past few years, you’ve probably seen people wearing straps around their arms or legs while training. These tight bands are used for blood flow restriction training. Now you’re asking, “what is blood flow restriction training, and should I try it?”. In short, blood flow restriction training or BFR training is used to restrict blood flow which creates the same conditions of resistance training by depleting the oxygen in the blood. Typically, we need to lift heavy loads or volume to achieve muscle growth or hypertrophy. With blood flow restriction training, you can lift lighter loads and still get bigger, more robust muscles. Olympic athletes to people at your local gym now use BFR training. This post will look at blood flow restriction training, the benefits, how to implement it into your workout, what to consider when buying BFR cuffs, and frequently asked questions.
WHAT IS BLOOD FLOW RESTRICTION TRAINING?
Blood flow restriction training is a training modality where resistance training, physical therapy movements, or aerobic exercise is done while blood flow is restricted through the use of an occlusion cuff or tourniquet on the arms or legs. Blood flow restriction training is also known as occlusion training, BFR training, or KAATSU training. The idea of blood flow restriction training is that it mimics the way muscles get fatigued during hypertrophy or strength workouts by depleting the oxygen levels in the blood. Under normal circumstances, it would require either lifting heavy loads or enough reps to deplete the oxygen levels in the muscles in the same way.
However, with blood flow restriction training, these same conditions of muscle fatigue are realized, which is needed for muscle growth. By reducing the need to lift heavy loads or work the muscles to fatigue, BFR training can be effective in rehabilitation circumstances where the patient should avoid placing too much stress on the joints or the cardiovascular system.
BRIEF HISTORY OF KAATSU OR BLOOD FLOW RESTRICTION
In 1937 the Journal of American Medicine published a study on blood flow restriction to regenerate tissue and increase walking ability in people who had lower body blood circulation issues. However, it wasn’t until nearly 30 years later when the man who is now synonymous with BRF training reimagined it, giving it a new lease on life.
In Japan during 1966, Dr. Yoshiaki Sato was at the young age of 18, (this was years before he became a doctor). He was at a Buddhist ceremony and sitting on the floor for an extended period in the “Seiza” position, which led to his legs becoming numb. To relieve this pain and numbness, he started to massage his calves. He finally realized that this pain and numbness was because of blood flow restriction due to the way he was sitting on his feet. This was Sato’s lightbulb moment when the concept of blood flow resistriction training began.
Sato took the next seven years to experiment through trial and error as to which bands, ropes, tubing, and pressures worked as he wanted. He meticulously tracked the results of his self-experiments, leading to several protocols that could safely and effectively alter the blood flow in his limbs. Little did he know how important those seven years of dedication to this new craft he created called KAATSU would become. The name KAATSU comes from the Japanese word (additional pressure). Sato ended up fracturing his ankle and damaged the ligaments around his knee during a ski trip around 1973.
Doctors told him that the injuries would take at least six months to heal. With the cast on his ankle, Sato started to apply his KAATSU methods on himself by using KAATSU bands on his upper leg above his injuries. While changing the application of pressure to his leg, he would do 30-second isometric exercises up to three times a day. This rehabilitation led to him healing his injuries within six weeks, all the while without any muscle atrophy.
After that, Sato continued to refine his treatment methods and techniques for the next 20 years then filed patents in 1994 for his KAATSU training bands. Since then, thousands of people have gone through Sato’s program to train instructors in his treatment methods. Throughout the 2000s, Sato’s work has been studied in multiple research collaborations worldwide, including national research foundations, universities, and even the US Department of Defense.
HOW DOES BLOOD FLOW RESTRICTION TRAINING WORK?
There are multiple physiological responses to blood flow restriction training. To perform BFR training, BFR cuffs/bands are wrapped around the upper arms and/or upper legs. The pressure from the bands partially restricts oxygen-depleted blood from the limbs to the heart. This restriction results in the muscles working in overdrive to pump the blood back to the heart.
The subject then goes through BFR training workouts that include a time of resting and exercise.
During the exercise, blood goes through the normal cycle of being pumped from the heart to the arteries, then limbs and veins surrounding the muscles, circulates back to the heart; rinse, and repeat. The BFR bands act as a floodgate as the muscles have to work harder to pump the venous blood past the bands back to the heart. This creates the sensation that the muscles are tired, similar to how they react to heavy resistance training. BFR training leads to increased muscle activation and greater muscle protein synthesis without lifting heavy loads.
Another physiological reaction resulting from BFR training is that the lack of oxygen in the muscles leads the central nervous systems to send signals to the brain that the muscles aren’t getting enough oxygen. The brain receives this message then, in turn, sends a status update to the endocrine system. The anterior pituitary gland in the brain then releases growth hormone to help with lipolysis (breakdown of fat), muscle cell reproduction, and muscle cell regeneration.
One more vital response is that BFR training triggers insulin growth hormone (IGF-1) to be released, which aids in hypertrophy, bone growth, and modulation of DNA synthesis.
Lastly, BFR training helps to target and train fast-twitch muscle fibers. Fast-twitch muscle fibers are responsible for anaerobic exercises like sprinting and jumping. BFR training affects the muscles at a cellular level where the lack of oxygen promotes protein synthesis, which adds to improved muscle repair and strength.
BENEFITS OF BLOOD FLOW RESTRICTION TRAINING
Blood flow restriction training offers numerous benefits because of the restriction of blood flow and oxygen-depleted blood. Let’s have a look at some of the health benefits surrounding this type of treatment.
May Reduce/Prevent of Muscular Atrophy: One of the best aspects of BFR training is that it can prevent muscles from atrophy in situations where intense resistance training isn’t feasible. This review looked at the results of 3 studies regarding BFR training and its effects on patients with leg immobilizations. Overall, it seems promising that BFR training can help to minimize muscular atrophy and strength reduction after immobilization. However, it’s important to note that these studies appeared to have some bias, so more research needs to be done in this arena.
May Increase Bone Mineral Density: A common claim of BFR training is that it helps maintain a positive balance on bone metabolism. This systematic review looked at four studies that showed BFR training showed increased bone formation markers through low-intensity exercise. However, more research needs to be conducted in this field to come to solid and definitive conclusions.
Enhanced Muscular Strength & Size: BFR training with low loads looks promising in delivering strength and muscle gains. This study compared high load resistance training of 80% one rep max and low load 30% one rep max in the unilateral knee extension exercise for young, healthy soccer players. Over 6 weeks, the heavy load group performed 4 sets of 12 reps while the low load group did 4 sets of 30, 15, 15, 15 twice a week. The testing looked at muscle strength and ultrasonographic parameters of both groups. The BFR training group scored slightly more significant improvements compared with the heavy load group.
Great for Rehabilitation: This study looked at low load resistance training for clinical applications regarding hypertrophy and muscular strength. We know that high load resistance training is the best way to stimulate new muscle and strength gains in normal circumstances. However, we’re now learning that BFR training has practical applications for rehabilitation where the subjects can only lift low loads. Here’s a systematic review and meta-analysis that found BFR training more effective than traditional low-load rehabilitation training.
Suitable for Elderly: BFR training can be beneficial for the elderly populations that can no longer move heavy loads with intensity because of aging and weakened joints and cardiovascular capacity. This meta-analysis reviewed 11 studies and found that low load training and walking with BFR training can effectively stimulate hypertrophy and strength gains in older populations. However, more research needs to be done to improve how BFR training can successfully be applied to elderly people.
Stimulates the release of Growth Hormone, IGF-1 & Testosterone: BFR training has been shown to stimulate the release of hormones that promote muscle growth and increased strength. This study looked at the results of BFR training on 25 healthy young men regarding three exercise protocols; control group, resistance exercise at 40% arterial occlusion press (AOP), and 70% AOP level. Testing was done at four-time points of the blood lactate, growth hormone, testosterone, and IGF-1. The results showed the higher-level group of AOP had the most significant increases in hormone secretion.
Low Impact on Joints & Muscle Tissue Stress: Using BFR training allows hypertrophy while using low loads. One risk of training with heavy resistance is the stress and tension that it puts on the joints. Over time people can experience joint pain and injuries by lifting heavyweights. BFR training can provide a safer means of getting to the same end goals of muscle and strength gain.
DOES BFR INCREASE MUSCLE SIZE?
Yes! Blood flow restriction training can lead to muscle hypertrophy (increased muscle size). The beauty of this training method is that you can achieve muscle growth by lifting as little as 30% of your one-rep max loads. This makes hypertrophy accessible for a broader range of people dealing with recovery from injury or surgery and those with joint problems, as they can bear heavy loads without further injuring themselves.
WHO SHOULDN’T USE BFR?
Blood flow restriction training is safe for most people, but as with most things, it can be potentially dangerous if done incorrectly or if used by the wrong groups. BFR has been proven safe and hasn’t resulted in serious harm for people who don’t have contraindications (risks) to BFR training. However, people who have blood clotting issues or cardiac preconditions should be hyper-aware of potential adverse side effects of BFR. As with any new training regimen, we always recommend consulting your doctor to get cleared for participation.
CONTRAINDICATIONS OF BFR TRAINING
There’s a complete list of potential contraindications of BFR training that can be found here. In general, people suffering from vascular or cardiac conditions can be at increased risk of complications from BFR training. Other common contraindications of BFR training include diabetes, hypertension, cardiac disease, pregnancy, varicose veins, or clotting disorders. When in doubt about whether or not you should undertake ANY new training modality speak with your physician to make sure all is well.
RISKS OF BFR TRAINING
Blood flow restriction training is considered relatively safe if applied correctly, but that doesn’t mean that some groups of people shouldn’t attempt BFR training. It’s essential to know the potential risks of using occlusion training. If not appropriately implemented, BRF could lead to complications as this method involves restricting the free flow of blood.
Here are a few risks of BRF training:
Blood Clotting: If you use too much pressure and restrict blood flow too much, you can risk triggering blood clots. These blood clots could result in pulmonary embolism, stroke, or even death.
Muscle Damage: Excess pressure from an occlusion band could result in muscle and/or nerve damage. The symptoms of damage resulting from BFR could be soreness, swelling, reduced range of motion, and overall muscle fatigue.
Rhabdomyolysis: This isn’t a common occurrence from BFR training, but negligence could lead to rhabdomyolysis, which is severe muscle damage. This is caused by the overabundance and release of myosin, which is a protein in the blood. In some cases, this can lead to kidney damage. Symptoms of rhabdomyolysis include extreme muscle soreness, pain, dark urine, joint pain, and overall weakness.
IS BLOOD FLOW RESTRICTION TRAINING SAFE?
Overall, blood flow restriction training is safe and effective for most people if appropriately implemented. For the most part, there’s no certification needed to apply blood flow restriction training methods; you must educate yourself on how to use it properly. If you’re a trainer, you should double-check any regulations in your area requiring formal training to administer BFR training. Suppose you’re looking to be educated on BFR training. In that case, there’s probably a no better place to look than the originator of the technique, Dr. Sato’s website, where he offers both training programs and BFR/KATTSU devices.
WHERE TO USE BFR CUFFS?
The placement of the BFR cuffs should be located at the upper arms or upper legs. Avoid using the cuffs below the elbows or knees.
IS BFR TRAINING GOOD FOR OTHER MUSCLES BESIDES LEGS AND ARMS?
While you will be placing the BFR cuffs on the upper arms and legs, the positive benefits can
also be transferred to other muscles. The central nervous system will recruit other muscles to help pick up the slack from the fatigued muscle so that force production stays high enough to complete the given exercise. This means that the non-restricted limbs can enjoy secondary benefits.
This study looked at how BFR training impacts the muscles when doing compound exercises like the bench press. They divided young men into two groups; blood flow restriction training and non-BFR training. The BFR group used pressure between 100mmHg – 160 mmHg. After two weeks, the BFR group showed 6% improvements in the one-rep max bench press while muscle thickness increased 8% in the triceps and 15% in the pec major. The non-BFR group didn’t see any improvements. There are other studies showing the positive cross transfer effects with BFR training.
HOW TO IMPLEMENT BFR INTO YOUR TRAINING
The usage of BFR training highly depends on your circumstances. For example, if you’re recovering from an injury or surgery, you would use BFR training as a rehabilitation tool. If you’re elderly and you have some joint issues, then you might use BFR training to keep your muscles from atrophying. If you’re a healthy person in good shape, you might use BFR training as another tool in the toolkit to keep your body in peak condition. For rehabilitation purposes and for groups of people that have any prior conditions, including age-related issues, then you should look to your health provider for clear guidance as to when and how to use BFR training.
Here’s a look at a few situations where you can implement BFR training into your regular workout routine:
Use For Isolation Exercises: BFR combined with high-intensity heavy load training is an excellent balance of training to get those muscle and strength gains you’ve been after. At the end of your workout, you can use BFR cuffs with isolation exercises such as triceps pushdowns, biceps curls, leg extensions, or leg curls. BFR cuffs can be great to get that muscle-burning pump towards the end of a workout by using light weights. Shoot for 4 sets of 30, 15, 15, 15 reps using loads around 20-40% of your one-rep max with rests of 30-45 seconds between sets.
Combine with Compound Exercises: You can use BFR training with multi-joint exercises such as bench press, squats, hip thrusts, overhead press and more. Even though you’re using the BFR cuffs on the limbs, other muscles involved in the lift can reap the rewards. Make sure you don’t go overboard with the loads you’re lifting here. Check your ego at the door, focus on executing each rep flawlessly and shoot for higher rep ranges.
Use for De-loading Periods: We often recommend a de-loading period in your regular training regimen to allow your body to recover and recuperate from lifting heavy loads. BFR training is an ideal training method to use when de-loading or healing. Try mixing in a week of BFR training into your workout schedule, which can be a light recovery session or even a whole week of BFR training once every 4 weeks. You can also try to use BFR training on specific exercises 2-3 times per week, just allow for proper rest and recovery between session.
Note: Make sure to leave the BFR cuffs on throughout the exercise and only remove after done with all BFR work.
WHAT TO LOOK FOR WHEN BUYING BFR CUFFS?
To properly execute BFR training, you’ll need to purchase some equipment if you don’t already have it. BFR training equipment can be referred to as BFR cuffs, occlusion bands, or BFR bands. To choose the best BFR cuffs, you can ask yourself the intended usage. For example, will you use it for your legs, arms, or both? Will you be the only person using it?
Here are some factors that you should consider before buying blood flow restriction cuffs:
Size: Blood flow restriction bands come in a variety of sizes and widths. If you’re planning on using them for only your arms, you may be able to look at the shorter options, but if you want to use them for leg exercises as well then, you’ll need larger ones. These days many brands are offering the BFR bands in packages of four so that you have two for the arms and two for the legs. Some standard lengths for BFR cuffs are in the neighborhood of 20-40 inches.
The other aspect of the size that’s important to look at is the width of the cuffs themselves. Most of the popular BFR cuffs will range from 1-4 inches wide. The narrower the BFR cuffs might be more uncomfortable as the surface area is less, which leads to more force or pressure in that area.
Material: BFR cuffs can be made from different materials that provide varying levels of durability and comfortability. The budget-friendly BFR cuffs are usually made of cotton and polyester blend with elastics sewn into it and secured with a Velcro strap. The buckles on the BFR bands are generally made with plastic or metal. BFR cuffs have different rigidity, so be sure to read some reviews before purchasing; this comes down to more of a personal preference. There are plenty of options on the market for BFR cuffs, and not all of them are built with the same quality, so do your homework if you’re looking for ones that will last. Always check return and warranty policies.
Pressure: There are generally two types of BFR cuffs; self-adjusted, where you’ll tighten the bands by pulling them tighter then locking the buckle in place, or pressurized cuffs that have a pump attached to increase or lower pressure. As you might have guessed, the self-adjusted pressure BFR bands are cheaper. They usually have number markings on the bands so that you know how tight you’re making them. The BFR cuffs with the handpump or automatic pump pressure gauge will tell you exactly how much pressure you’ve applied, which gives you a more accurate picture while doing your BFR training. We believe that this is one factor of BFR bands that is essential. The pressure gauge allows you to control how much pressure is being applied, making BFR training safer and more effective. The BFR cuffs with pressure gauges will usually go up to 300 mmHg of pressure.
Budget: Blood flow restriction cuffs have a wide array of pricing options. On the low end, you could spend $10-20 for a set of two BFR bands for arms or $20-$50 for a set of 4 bands that can be used on arms and legs. These cheaper bands will be self-adjusted, and you’ll find plenty of options on Amazon. On the pricier side of things, BFR cuffs can set you back $150-$600; these will have a handpump or automatic pressure gauge. Some BFR bands even have wireless APPS that monitor the pressure levels and track training progress.
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CAN I USE KNEE WRAPS FOR BFR TRAINING?
Yes, knee wraps can be used in place of BFR cuffs but might not be the ideal tool for blood flow restriction training because it’s harder to judge the pressure you’re using. Self-adjusted BFR bands will have markings so that you know how tight the band is, while the more expensive options will have pressure gauges that tell you the exact amount of pressure being applied. Knowing the amount of pressure being applied allows you to train more consistently from workout to workout.
Using a tool like knee wraps or other elastic devices is sometimes referred to as practical BFR. The key point when using these different tools for BFR is to try to find the sweet spot for venous blood flow restriction without compromising arterial blood flow. In some cases, we’ve seen places like Bodybuilding.com lab do tests where people used perceived pressure ratings of 0, 7 0r 10 out of 10. They found the 7 out of 10 perceived pressures to be where the greatest results were found while creating venous restriction.
ARE BFR CUFFS WORTH IT?
Yes, we think BFR cuffs are worth purchasing if you’re interested in taking advantage of all the benefits blood flow restriction training has to offer. BFR training can be another weapon in your arsenal that allows you to break through training plateaus or recover quicker from injury.
FINAL NOTE
We hope you know a little more about what blood flow restriction training is and how this training method can offer some fantastic benefits if done right. Just remember to be safe when using BFR training in your workouts. Many BFR cuffs these days will come with PDF guides or courses to educate you on best practices. Check out Dr. Sato’s website if you want information from the man who reintroduced and perfected this novel training approach. We’re excited to see the future and how BFR training will continue to surprise us with its benefits.
Let us know if you’ve tried BFR training and what you think about it!
Kiel DiGiovanni
Author