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The evolution of BFR

Following six years of dedicated testing, research and refinement, Hytro was born. Our innovative technology was patented in 2020, but here is where it started.

Man adjusting strap on his Hytro BFR Tee

The Beginning (1966-95)

Sometimes the greatest of ideas come from the least likely of places. That was certainly the case with BFR, discovered in Japan in 1966 by Dr. Yoshiaki Sato. Sato noticed the transformative power of BFR while attending a Buddhist festival, for which he was required to kneel for long periods. With the pressure in his legs building, Sato found the kneeling position becoming increasingly uncomfortable. In an attempt to relieve the pain, he massaged his aching legs. The change was instant. Sato noted that the ‘pump’ he felt was similar to that of an intense workout. This, he hypothesized, was due to the reduction in blood flow in his lower limbs while he was kneeling. Intrigued, he vowed to research the effect further.

Initially called Kaatsu, Sato decided to develop a product to achieve the effect of blood flow restriction. He tried out ropes, bands and even bicycle tubes, testing them on himself before once again refining his product until he had produced an effective protocol.

It wasn’t until 1994 that Sato applied for his first patent. Within twelve months, academic study on BFR Training had begun at the University of Toronto. Since then, more than a thousand academic papers have been published on the topic.

The Initial Growth (1995-2013)

As news of BFR spread, gym-goers and trainers tried out the new training technique for themselves – with varying degrees of success. With knowledge still low and safety protocol minimal, many attempted to restrict blood flow with whatever they could lay their hands on. Elastic bands, scarves and even socks were used, wrapped tightly around the working limb in the hope of producing the same pump that Dr. Sato felt all of those years ago.

There’s a reason that Hytro BFR wearables aren’t made of elastic bands. While it is possible to occlude the muscle with most cuffs, few provide comfort and even fewer are considered safe. Early adopters were left with two choices: cheap BFR cuffs or bands that were uncomfortable and scratched the skin, or more expensive pressurised cuffs intended for use by qualified professionals. Those who went with the first option often suffered from the incorrect application of BFR. They struggled to put on their homemade bands which were uncomfortable and scratched the skin, then placed them over the wrong area of the muscle – if they even remembered to pack them in their gym bags. The second option, meanwhile, was inaccessible to most people due to the cost and need for qualified supervision.

“It’s the safety, placement, utility, comfort and positioning that can vary massively and ultimately impact results,” said Hytro founder, Dr. Warren Bradley. “The positioning on the limb is crucial. Pressurised cuffs are a valuable tool in a clinical setting but must be used with qualified supervision, meaning they’re not a realistic option for the vast majority of people. They are cumbersome and time-consuming to apply safely and use, reducing their scope of practice to rehab.”

During this period, academic research continued to develop and sophisticate BFR Training. A 2013 study, in particular, was crucial in developing safety protocol. While it had thus far been widely agreed that pressurised cuffs were the most effective way of carrying out BFR, JM Wilson et al. suggested that a perceived scale of tightness could instead be a viable method for determining the appropriate level of cuff restriction. Working with elasticated knee wraps in practical BFR, they found that a perceived tightness of 7/10 was the safest and most effective way for BFR Training to be carried out. Even better, it could be done without the need for qualified supervision.

The Explosion (2014-21)

In 2014, while working with England Rugby, Warren had the idea of integrating BFR straps within clothing. He’d utilise the perceived tightness suggested by Wilson et al. while positioning the strap in the appropriate place for a safe and effective workout – finally providing a third option for gym-goers that would prove accessible, comfortable and effective, unlike any other BFR tool out there.

Following six years of dedicated testing, research and refinement, Hytro was born. Our innovative technology was patented in 2020, meaning that it is just as protected as those who use our wearables.

Making BFR Training safer and more accessible than ever before, Hytro BFR wearables use specific strap widths individualised for both the arms and legs (coming soon) along with material compositions recommended for the best and most comfortable form of safe occlusion. The integrated straps ensure there is no need for supervision, while also avoiding the improper positioning and discomfort of the straps seen with many regular BFR cuffs or bands. Our wearables, therefore, maximise results thanks to their reliance on scientific details and academic research to give the best and safest of workouts.

And we’re only just getting started.

Man wearing Hytro BFR Tee whilst performing pull up

The Future

Our first Hytro BFR wearables focused on the upper body. To complement this, we’re currently working on lower body wearables. A partnership with Queen Mary University of London and Pure Sports Medicine will see us conduct collaborative research to continue to enhance our products and confirm our wearables’ efficacy. This is just one example of our commitment to scientific research in a bid to further the use and understanding of BFR, making the extraordinary training technique accessible to all.

BFR Training has come a long way since its humble beginnings in Japan. Knowledge and understanding have transformed training around the world. So put down your cuffs, bands, ropes or bicycle tyres and pick up some Hytro BFR wearables for the safest, most effective BFR workout possible.


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