Blood Flow Modification (BFM) and Recovery

History of BFM

In the 1960’s Yoshiaki Sato stood up after spending several hours in a kneeling position while at a Japanese funeral.  His calves cramped up and he felt like he had just put his legs through a brutal leg workout.  In 1973, he broke his leg skiing and was put into a long leg cast for six weeks. During his immobilization, Sato initiated the first “blood flow modification” recovery by wrapping belts around his leg while performing isometric exercises.  Doctors were shocked when his leg was not atrophied or tender when the cast was removed. Throughout the 1970s, Sato experimented Blood Flow Modification techniques on himself and other Japanese body builders. During the 1980s, he began a personal training clinic, introducing “occlusion training”.  Dr. Sato started formal research in the 1990s, and developed “KAATSU” pneumatic bands. “Ka” means “additional” and “Atsu” means “pressure.”

BFM has gained more wide-spread popularity as it started being used for military personnel who were struggling to improve muscle strength and size in their injured limbs after blast injuries, amputations and limb salvage procedures. When attempting to lift heavy weights, they were significantly limited due to pain and weakness. With the help of BFR training, they were able to achieve their strengthening goals using lighter weights. Olympic athletes have since caught on to BFR taking workouts to the point of fatigue without the heavy lifting. Now BFR is becoming more popular in outpatient physical therapy as well, as it can help minimize the effects of limited extremity use.

What is BFM?

BFM modifies the flow of blood entering the limb and limits the amount of blood leaving the limb.  This modification of blood flow forces blood into the capalaries to create more vascular elastiscity, vasodiolation, and NO2 release.  During BFM training, a patient or athlete works out with a narrow, inflatable band around the upper portions of the exercising arm or leg. Doing this produces a systemic response comparative to heavy weight training. Performing high repetitions of a particular exercise while wearing the inflatable band and using light weights will allow the user to receive the strengthening benefits of heavy lifting without the stress to tissues that may be healing from a recent injury or surgery.

How Does This Work?

In a nutshell, exercising with lighter weights while using blood flow modification causes a local disturbance of homeostasis, as the working muscle does not receive enough blood flow to sustain contractions. This creates a release of autonomic and anabolic hormones that move throughout the body.  This systemic response augments the local response, causing increased protein synthesis. Because little to no damage is done to the soft tissue by avoiding heavy weight lifting, improvements in strength and endurance can come quickly. All tissues both proximal and distal to the blood flow modification can benefit from these effects.

Who Benefits from BFM?

BFM training can be performed in a regular fitness routine, but can also be safely performed under the supervision of trained professionals in outpatient physical therapy clinics. BFM can safely be used on patients in the acute phase of rehabilitation following most upper or lower extremity surgeries, including ACL reconstruction, meniscectomy, hip/knee replacement, rotator cuff repair or any tendon repair.


Research has shown BFM can minimize loss of muscle mass and decrease bony healing time during the early immobilization phases, allowing patients to improve both muscle size and strength without the stress of heavy lifting on healing soft tissue. Patients with osteoarthritis, rheumatoid arthritis, osteopenia or osteoporosis may also benefit from BFM. Additionally, BFM has been utilized after strokes or spinal cord injuries and with athletes who want to improve performance.


Research has shown that BFM is not only comfortable for the user, but also safe and effective when exercises are performed appropriately.


KAATSU is not Blood Flow Restriction (BFR) due to a variety of factors including the specific design and engineering of the KAATSU Air Bands.

The stretchable Bands are designed to reduce venous flow (blood flow back to the torso). The Bands do not occlude arterial flow (blood flow to the limbs). This is very different from blood pressure cuffs that are specifically designed to occlude (cut off) blood flow to the limbs.

The width of the Bands is also much different than a blood pressure cuff (i.e., it avoids arterial flow occlusion). The Bands very importantly allows for ease of movement of the limbs (for walking, running, cycling, calisthenics, physical therapy, swimming, throwing, pulling, pushing or any specific movements required in sports or fitness).

The Bands include baffles and a stretchable air bladder that inflates uniformly and towards the limb, precisely controlled by the KAATSU monitoring units (e.g., KAATSU Master 2.0, KAATSU Nano, KAATSU Wearables).

The Bands can be immediately deflated by either pushing buttons on the monitoring units, depressing the value on the connectors, or releasing the Velcro on the Bands.

What are some health benefits of BFM?

Nitric Oxide Production

  • KAATSU leads to production of VEGF (vascular endothelial growth factor) and nitric oxide in the body.
  • Nitric oxide allows blood vessels to constrict and relax, and also regulates the inflammatory cells in the blood vessel walls.

Growth hormone Secretion

  • Lactic acid builds up in the muscle causing the pituitary gland to secrete growth hormone
  • Growth hormone is secreted in large amounts activating the body’s metabolism


Slow twitch muscles rely on oxygen to fuel them.  When a conductiong low intensity training with BFM, the muscles experience a state of hypoxia (lack of O2).  Because the slow twitch muscles are starved of O2, fast twitch are forced to spring to life and start to engage and work.  This gives users the ability to

Is a warm-up or cool-down necessary?

In general, BFM is performed at intensities normally used for a warm-up set, such as 20-40% of your one-rep max (1RM). As such, we recommend a light, general warm-up of around five minutes, such as walking or light cycling, or use the cycle mode of the KAATSU cycle 2.0.

Where should I apply the bands?

Bands should be placed at the top of the leg or top of the arm.  This will provide the best modification of blood flow and greatest range of motion for conducting exercises.

How heavy should I lift with BFM?

The primary advantage to BFM is that you can increase muscle size at very low intensities. In fact, some research found that individuals who walked with BFM at low intensities could actually increase quad muscle size. However, we have found that resistance training results in greater benefits in muscle and strength than walking.  During resistance training it is recommended to lift between 20-40% of 1RM, at a high rep (20-30x per set).

Will BFM help chest, back and core?

Many people think that BFR training is just for the arms and the legs, but it be used for the chest, back, and glutes.  When you modify the blood flow of the limb, there is an increase in muscle activation in the non-restricted limb muscle.

By wrapping the arms or legs, the nervous system senses extreme fatigue in the limbs. This causes the body to do whatever it can to maintain force and keep itself from failing. To compensate, your nervous system recruits more muscle from nonrestricted limbs.

For example, research published in Clinical Physiology and Functional Imaging found that modifying blood flow to the arms and performing the bench press actually resulted in a 16 percent increase in muscle activation of the chest.

What are the recovery demands of BFM versus other isolation training?

Research has found that even though BFM caused greater fatigue immediately after the exercise session, there were no increases in muscle damage or declines in force or power 24 hours later.

Is it necessary or advisable to go to failure with BFM?

BFM taps into a major growth mechanism by recruiting the larger, fast-twitch muscle fibers. Fast-twitch muscle fibers are activated by either heavy resistance or fatigue. Research shows that the closer you get to nearing failure, the greater fast-twitch muscle-fiber recruitment becomes.


Yes.  The KAATSU Cycle is designed to apply and hold for 30 seconds with 10 seconds of no pressure.  Using the cycle mode

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