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Blood Flow Restriction Training: B-Strong Band Kit Review

A natural part of the aging process is the gradual loss of muscle mass. This process, known as sarcopenia, poses one of the most significant risks for loss of mobility, function, and independence as we get older. In fact, research has shown that loss of muscle mass is a good predictor of mortality

The main way to prevent muscle loss as we age, is through load bearing resistance training.  The challenge is that resistance training routines require weights or other gym equipment and demand that you work at near maximal load to gain muscle.  Not to mention that it is a common cause of injury and implies a significant time investment.  

That’s why we are always looking for innovative ways to help you build muscle and why we are particularly excited about the B-Strong Training System, a workout kit that uses an amazing technique called blood flow restriction (BFR) training.   

We did exhaustive research on the science behind BFR training and the B-Strong system.  This is what we found.

The B-Strong Training System

The B-Strong Training System is the brainchild of Dr. Jim Stray-Gundrsen, a world-renowned 

expert in sports medicine, exercise physiology and training for sport performance.  This patent-pending system consists of especially designed blood flow restriction bands that you wear on your arms and legs while doing any type of exercise.  

The benefits of using the B Strong system include:

  • Achieve the same benefits of using heavy weights without risking injury
  • Activate a higher percentage of muscle fibers with less effort
  • Rapidly Increase strength
  • Increase bone density
  • Reduce body fat 
  • No muscle soreness after your workout
  • Reduce overall stress on joints without sacrificing training effectiveness
  • Increased formation of blood vessels in the muscle

We know this might sound too good to be true.  We thought the same thing.  That’s why we did a serious deep dive into the topic. We can tell you that it checks out.  Read on.


Nowgevity Research Report

What is Sarcopenia

How blood flow restriction training came about

What is the science behind BFR training

Who developed the B Strong Training System

What we like about the B Strong 


What is Sarcopenia

Sarcopenia is the loss of skeletal muscle mass and function as we age.  We begin to lose muscle mass after age thirty, at an estimated rate of approximately 1% per year.  This rate starts to accelerate after age 50 and speeds up significantly once we cross 70 years of age.   

The causal mechanisms of sarcopenia have not yet been clearly defined.  However loss of muscle mass has been established as a clear predictor of mortality in middle-aged and older adults.  

Besides leading to an earlier death, sarcopenia impacts longevity indirectly, as it makes us more prone to falls and fractures. This is in part  because we mostly lose what's known as type II fast-twitch muscle fibers. As their name suggests, these are the muscle fibers that allow us to react quickly to recover from a loss of balance or an unexpected obstacle.  

This type of accidents as we age, often lead to broken hips and other fractures that increase our mortality risk. Furthermore, the loss of mobility and independence are also associated with declines in mental wellbeing.

An accompanying effect of sarcopenia is the loss of muscle strength (known as dynapenia), which drops at an even higher rate than muscle mass. Loss of strength not only starts to limit our lifestyle choices as we age, but frailty is another clearly identified  predictor of mortality

But there’s good news. Sarcopenia can be slowed and even reversed with exercise, specifically through resistance training (naturally, nutrition also plays a role).  This type of exercise stimulates the growth of new muscle fibers.  In particular, intense resistance training can help regenerate the fast-twitch muscle fibers that are primarily affected by sarcopenia.  

However, the challenge with most resistance training routines is that they require equipment, they are time intensive and, most importantly, require you to work at near maximal load capacity to generate muscle.  This can often lead to injuries especially as we get older. Setting that aside, the reality is that many of us currently don’t have access to a gym.  And, let’s face it, gym routines can get kind of boring.

That’s why we are always on the lookout for alternative methodologies for building and maintaining muscle and why we are particularly excited about a relatively unknown technique known as blood flow restriction training.

How BFR Training Came About

Although blood flow restriction as a method for enhancing health and fitness is relatively new to the US, it was developed several decades ago in Japan by Dr. Yoshiaki Sato. The original idea for this technique came to Dr. Sato in 1966 when, after kneeling for a prolonged period during a Buddhist funeral service, he recognized that his lower legs felt the same as if he had finished an intense workout.  He got curious about this effect and started to investigate

Dr. Yoshiaki Sato, inventor of blood flow restriction training

A few years later, Dr Sato fractured his ankle and injured his knee while alpine skiing. As a result he was placed in a full-length cast to immobilize his leg.  In order to prevent the muscle atrophy that inevitably happens when you immobilize alim, Dr. Sato decided to experiment with some of the techniques he had devised.  He started performing isometric exercises with his injured leg, using different types of belts and bands at the top of his leg to partially restrict the blood flow. 

Six weeks later, when his doctors removed his cast they were amazed to find that his leg muscles had not atrophied as expected.  They were also surprised to find that his bone fracture had healed a few weeks ahead of schedule.  They concluded that the blood flow restriction exercises that Dr. Sato had been performing were somehow related to his better than expected outcome.

This inspired Dr. Sato to dedicate himself to researching, perfecting, and applying blood flow restriction methods to various types of training contexts.  Through years of trial and error he eventually consolidated his know-how into a methodology he named Kaatsu, which in Japanese means “additional pressure.” 

The consistently positive results achieved through the use of BFR training started to attract the attention of the scientific community and the first formal scientific study of its effects was published in 1998.  Since then a lot of research has been done on the effects of BFR and today there is a strong body of evidence consistently pointing to its positive effects.  

As a result, BFR has evolved into a unique training method used by professional and high-performance athletes to maintain their muscle conditioning and to speed up recovery from injuries.

What is the Science Behind BFR training

As its name suggests, BFR training consists of restricting the venous outflow from your extremities as you perform any type of exercise.  This restriction is achieved by wearing a band or cuff at the top of your arms and/or legs (a key consideration of BFR is the amount of pressure applied, see below).

By restricting the regular blood flow out of your muscles while they are working, you effectively reduce the amount of oxygen they have available.  This causes them to get fatigued more quickly which in turns triggers a cascade of reactions that ultimately lead to building new muscle fibers.

You probably remember from high school anatomy that veins return blood from muscles and organs back to the heart.  When you partially compress the veins, you slow the rate at which oxygenated blood flows back into the muscle from the heart. 

When you start exercising you mobilize a certain amount of muscle fibers.  As these muscle fibers work and get fatigued additional ones get recruited to sustain the effort. Typically, the first type of muscle fibers that get recruited to work during exercise are what are known as slow-twitch muscles (also called type I).  These fibers rely on oxygen to fuel the muscle contractions.  Once their capacity gets depleted, the fast twitch fibers (known as type II) get recruited to continue doing the work. Fast twitch fibers are anaerobic which means they don’t need oxygen to power the muscle.

By limiting oxygen availability to the muscles, BFR training accelerates the exhaustion of slow-twitch muscle and the recruitment of fast-twitch fibers to sustain the effort. This allows you to work the entire muscle more quickly and effectively. 

As the muscles fibers work to exhaustion they produce a build-up of lactic acid which in turn produces two effects.  Locally, it stimulates the activation of what is known as the mTOR pathway, which in turn triggers protein synthesis in the muscle to produce new muscle fibers. 

The build-up of lactate is also detected by the central nervous system (CNS)  which send signals to the brain (specifically the pituitary gland) to set in motion a repair and recovery process through the release of a cascade of hormones—including growth hormone (GH), vascular endothelial growth factor (VEGF), myostatin (GD8), heat shock protein (HSP), and nitric oxide synthases-1.  All of these are involved in the process of creating new muscle fibers and blood vessels.

One huge benefit of BFR training is that you do not need to work as intensely as you normally do to fully recruit and exhaust your muscle fibers. Whereas the muscle gains from resistance training using weights or machines are achieve at loads that are at 80%-90% of an individual’s one-rep maximum capacity, achieving the same results with BFR training only requires you to work with a load equivalent to 20%-30% of your one-rep max.  This also drastically reduces the risk of injury.  

Another surprising effect of BFR exercise is that it helps build up all muscles involved in the exercise, not just those that are being subjected to vascular restriction.  So, for example if you are doing a push up while wearing BFR cuffs on your arms, blood flow will be restricted to the triceps but not the pectoral muscles.  However, the latter will also see the benefit from the response of the central nervous system. 

It is believed this happens because the brain does not distinguish between the restricted muscles that are sending distress signals to the central nervous system, from those that are upstream.  The result is that all the muscles involved benefit from the body's hormonal response. 

Importantly, recovery after BFR training is much quicker than after traditional weight or resistance training.  That’s because you are using a relatively light load and are therefore not tearing the muscle fibers, so you don’t experience what is known as delayed onset muscle soreness.  In essence, you are getting the full benefits of heavy weight training without having to be sore for days.

Lastly, there is also evidence that BFR training can have a positive effect on stimulating bone strength and the creation of new blood vessels in the muscle. 

(To go deeper, see the list of BFR research studies below) 

Summary of BFR benefits: 

  • Low weight loads required to achieve the same benefits of traditional resistance training.  This leads to lower joint strain and lower risk of injury 
  • Minimal next day soreness (DOMS)
  • Increases in bone density
  • Increased formation of blood vessels in the muscle (angiogenic stimulation)
  • Improvement in strength (10-15% improvement after 10-20 sessions)
  • Reduction in body fat (the release of growth hormone stimulates the breakdown of fat to use as fuel sources).  People become 5%-10% leaner after 10-20 sessions

Who Developed the B Strong Training System

Until the development of B Strong, blood flow restriction training was difficult to access because of the cost of the equipment required and the specific know-how necessary to do it properly and safely.  This meant that for the most part the use of BFR remained limited to high-performance athletes and physical therapy clinics. 

This all changed  when Dr. Jim Stray-Gundersen decided to come up with a solution that can be used by anyone, anywhere.

Dr. Jim is one of the world’s foremost experts in BFR and has been a pioneer of its use in the US.  He became a board-certified general surgeon in 1985 and completed his post-doctoral fellowships on cardiovascular physiology and human nutrition at the University of Texas Southwestern Medical School.  After graduating he was invited to join the faculty and he spent the next 20 years teaching and conducting research focused on sports performance.  During his time at UTSW, Dr. Jim also helped build and direct two human-performance centers at St. Paul and Baylor University hospitals. 

During his career of over 40 years, Dr. Jim has served on the medical committees of the International Olympics, FIFA, as well as the International federations of Ski, Skating and Biathlon.  He is also the sports science advisor for the US Ski and Snowboard Federation and leads human performance and altitude camps for many Olympic athletes and the Navy Seals.  Lastly, he runs the SG Performance Medicine Center and Sport Technologies for Maximal Athletic Performance in Texas.  

When Dr. Jim Stray-Gundersen discovered the concept of BFR around 2012, he had been working in the world of sports medicine and exercise physiology for several decades.  He mostly worked with elite athletes and clinical populations. It didn’t take him long to see the potential that BFR training could have for people of all ages. The trouble was, the technology wasn’t accessible.

He decided to travel to Japan to meet Dr. Sato to learn and master the science and techniques of BFR.  He started using BFR with his athletes and saw consistently positive results.  One anecdote of his experience that stands out was the work he did with Olympic ski jumper Todd Lodwick.  Just 4 weeks ahead of the Sochi Olympics Todd had an accident on a  ski jump, fracturing his arm and tearing his rotator cuff. Todd thought he was going to have to miss the competitions, but working with Dr. Jim, he started doing physical therapy with BFR and recuperated in time to participate. 

Based on this and other similar experiences with other athletes, Dr Jim decided to design a BFR system that could be portable and accessible to the general public. He teamed up with entrepreneur Sean Whalen and in 2017, launched the B Strong. 

The  B Strong system is now used broadly by elite level athletes, professional sports leagues, and physical rehabilitation centers as a safe and efficient method to maximize human performance, resilience, and health. 

“B Strong is a paradigm shift in the way we exercise. You can now exercise smarter, safer, and improve your overall strength and fitness in less time with greater results. The benefits of BFR training lead to overall health and wellness for the entire population. It can be done anywhere, anytime, by anyone – young or old – regardless of your fitness level.” 

Dr. Jim Stray-Gundersen

What We Like the Best About B Strong

Besides the credibility that Dr Jim brings with his over 40 years of experience in sports medicine and working with elite, high-performance athletes, there are a number of features that we like about the product:


The key feature to look for in a BFR system is safety.  BFR training systems use pneumatic cuffs that apply pressure to your limbs to restrict the venous blood flow.  However, the restriction of blood flow to the limbs should never get to a point where the veins are occluded, stopping the blood flow completely. More importantly, the arterial flow of blood coming into the muscle should not be restricted at all.   

The B Strong bands are designed to avoid venous occlusion or any restriction to the arterial inflow. Their outer layer is made of an elastic material that expands when the muscle contracts, ensuring that blood continues to flow, though at a restricted rate.  

This contrasts with systems used in physical therapy clinics that use blood pressure cuffs with a rigid outer layer or surgical tourniquets.  These systems require you to be tethered to a monitor to ensure that blood is flowing at all times.  

B Strong and Katsu (the system developed by Dr. Sato in Japan) are the only two BFR devices that use elastic inflatable cuffs.  However, they operate somewhat differently.  When you pump up a Kaatsu band it expands. The elasticity is built into the fabric of the band.  By contrast, when you inflate a B Strong cuff it contracts.  The elastic elements are induced by a multiple barrel design of their cuff. 

In this video Dr. explains the safety feature of the B Strong system.

While we found other companies selling blood flow restriction bands, we did not feel comfortable with the lack of information provided on their product from a safety standpoint.

Ease of Use

The B Strong system is lightweight (<3 lbs), compact and portable so that you can use it anywhere you go.  Many elite athletes use the system while on the road when they don’t have a lot of time to work out or access to a training facility.

The system is supported by a Guidance App that acts as your instructor.  It uses proprietary algorithms to choose the appropriate starting cuff pressures for you based on your age, fitness level, and desired intensity of exercise.  It also tracks your history and helps adjust your pressures as you progress.  

The Guidance App contains video tutorials providing sample exercises to get started and suggesting different types of training routines.  The App also supports multiple users, so you can share your equipment.

The only drawback we found with the Guidance App is that it is browser-based rather than a full-fledged mobile app.


The B Strong cuffs are made of industrial grade materials used in marine applications. The Velcro pads are able to withstand over 10,000 cycles of closing and opening. Once properly placed, the low profile of the cuffs allows for full range of motion and doesn’t interfere with training. You can use them during any type of exercise including weight lifting, running, biking, doing yoga and even swimming.

Details about the B-Strong Training System

The system includes two arm and two leg blood flow restriction bands, a hand pump, carrying case, and access to the Guidance App. The sizes of the bands cover limb circumferences ranging from 18cm - 99cm (7in - 39in). 

A worthwhile investment in your future self

Longevity is no accident, and performing at your maximum is not luck. It’s intentional. To live longer, build muscle. To build muscle faster, we recommend the B Strong Training System. 

When it comes down to it, the B Strong System really is the only reasonably priced, safe option to practice BFR at home or on the road. 

For reference,  the Kaatsu system retails for $5,350 for the individual use model.  There is also a $25 monthly support and maintenance fee starting after 24 months of ownership.  Other systems, like Delfi’s PTSii Personalized Tourniquet System are only sold to physical therapy clinics and are much more expensive. 

At $430 the B-Strong System won’t break the bank and will likely help you get stronger and live longer.  

Note: although the system is safe, there are contraindications for using blood flow restriction training, such as pregnancy, certain medical conditions, and diseases. As with any other exercise program, we recommend consulting first with your primary care provider.


Resources & References

Blood Flow Restriction Training: Anti Aging Medicine For The Busy Baby Boomer

In this video taken at The Institute for Human & Machine Cognition,  Dr. Jim Stray-Gundersen presents some of the scientific evidence showing the many benefits of BFR training. 



Stem Talk IHMC - Dr Jim Stray-Gundersen Explains How Blood Flow Restriction Training Builds Muscle And Improves Performance 

Dave Asprey - Bulletproof Radio: How Blood Flow Restriction Can Revolutionize Your Fitness

Nourish Balance Thrive - Blood Flow Restriction Training for Improved Strength, Performance, and Healthspan

Kathy Smith - Blood Flow Restriction Training… A True Fitness Game-Change


Effects of Blood Flow Restriction Training on Muscular Strength and Hypertrophy in Older Individuals: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis reveals that Low Load-BFR and walking with BFR is an effective interventional approach to stimulate muscle hypertrophy and strength gains in older populations. 

BFR Increases Quality of Walking Exercises

Finding: BFR walking typically resulted in a 2.5-4.5 fold greater improvement in performance on all measures of physical function compared with walking control group among older adults

Muscle fiber cross-sectional area is increased after two weeks of twice daily KAATSU-resistance training

The purpose of this study was to examine the effect of low-intensity (20% of 1-Rep Max) resistance training (LIT) combined with restriction of muscular venous blood flow (BFR) on muscle fiber size using a biopsy sample.  Mean relative change in 1-RM squat strength was 14% in the LIT-BFR and 9% in the LIT control after two weeks of the training.

Effect of aerobic exercise training with and without BFR on aerobic capacity in healthy young adults: a systematic review with meta-analysis

Aerobic exercise training (ET) with BFR elicits a significantly greater aerobic capacity (AC) than aerobic ET without BFR in healthy young adults. Low-to-moderate intensity aerobic ET with BFR elicited a greater improvement in AC than aerobic ET without BFR.  However, high-intensity aerobic ET with BFR did not elicit an improvement in AC over high-intensity aerobic ET without BFR.

Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans

Repetitive restriction of muscle blood flow enhances mTOR signaling pathways in a rat model

Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion

Blood flow-restricted exercise in space - Extreme Physiology & Medicine

Proliferation of myogenic stem cells in human skeletal muscle in response to low-load resistance training with blood flow restriction

Blood flow-restricted strength training displays high functional and biological efficacy in women: a within-subject comparison with high-load strength training

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