Richard Graves (00:01.196)
Dr. Warren Bradley, welcome back to the Science for Sport podcast. Great to have you on the show again. For those that perhaps haven't caught previous episodes when we've discussed BFR, blood flow restriction therapy, just give our listeners a brief resume, your background, and how we've come to be where we are right now.

Warren (00:21.028)
Yeah, just start off and say it's awesome to catch up again, Richard, so thank you for having me on. I'll keep this one brief.

So I worked in professional sports for just over a decade in the Premier League International Rugby. Sports scientist by trade, did a PhD in exercise physiology, and essentially it led me to using a technique called blood flow restriction. And at the time the devices were pretty complex and cumbersome, very effective, but they were requiring supervision. They were kind of medically kind of trained individuals using them. So essentially, I created a way to make it more accessible and safe to use without supervision and unlocked that.

for the world to use for things like recovery, priming tissues prior to exercise and training. And yeah, that's that's hopefully what we're gonna go into a little bit today around the World Cup.

Richard Graves (01:07.744)
Yeah, absolutely. A few weeks ago we had Joe Truman on, the cyclist for Team GB. He was talking about how he uses BFR and how it impacts him in professional cycling. This is something that is getting increased traction across all sports at an elite level. So just remind us again exactly what BFR is.

Warren (01:29.04)
Yeah, I think that's a really interesting point because living inside the four walls of sport, we've had blood flow restriction for 65, 70 years, so it's nothing new. What is new is the application. And essentially what what it does is it

Increases the demand on the muscle tissues to drive greater adaptation. So essentially, by applying a strong restrictive stimulus to the top of the limb, so the armpits or the groin, we're going to trap blood in the muscles. And when you trap blood in the muscles, you get stressful metabolites building up, like lactate, you know, that burning sensation. And once that fills up in the tissue.

It magnifies the difficulty of anything you choose to do thereafter and therefore drives greater adaptations, whether that's strength, muscle building, endurance capacity, or whether that's actually recovery or warming up tissues beforehand, you pick a protocol to deliver your desired goal. But BFR is the way, the vehicle to magnify the outcomes.

Richard Graves (02:26.638)
Now of course when we talk about this year's World Cup we're talking about the biggest World Cup in the history of the event. 104 games being played across three countries, four different time zones, 48 teams being involved every minute, every hour, every session is absolutely critical if you're competing in a competition of this nature. So in your eyes where does BFR have the potential to have the greatest impact?

Warren (02:56.857)
Yeah, I think again you raise a really important point. not only is there kind of more squads, more logistics, more travel for for a lot of the teams, but there's a lot of teams coming off a punishing domestic season, you know, like in in England, the Premier League, they've they've barely finished and they're going straight into the World Cup. So these players are under high demands and high fatigue and high stress. So blood flow restriction comes in,

As a way to mitigate the stresses and kind of prepare the bodies and tissues for performance. So people have heard of blood flow restriction in the context of recovery. But actually, because it's able to improve the robustness of joints, of you know, structural tissues, improve bone mineral density, it's not just a recovery tool. It's actually able to keep players ready and available to play. And if you have your best players available to play, you have a higher chance of winning, right? So yeah, but it's it's not just one.

Bud flow restriction can be used across a multitude of different ways, but essentially keeping players ready and available to play.

Richard Graves (03:57.443)
Yeah, I'm glad you've touched upon that because in a tournament of this nature, obviously, players are managing fatigue. They're trying to effectively manage recovery time in order to get themselves back on the training ground and match ready for the next challenge that comes up. So in this scenario, when is blood flow restriction appropriate and when might it be more appropriate to use more traditional strength and conditioning schedules?

Warren (04:24.138)
Yeah, it's another great question. So it really depends on their program for the World Cup. So we work with six or seven teams of this year's World Cup, including, you know, England, Belgium, USA, etc., and others. And they use it in a very similar way at the core basis of recovery, but some of them use it for priming prior to competition to warm-up tissues. Some of them have used it for

The exhausting long haul travel. So for England in particular, who've done, I think it's over 6,000 miles they've covered, is it's mental. It's one of the highest travel demands of any team at the World Cup. They're at a a disadvantage immediately because of the stresses involved with long haul travel. So Hydro has become a trusted tool for them to use while traveling on a flight. Because what Hydro can do is deliver an improved or magnified circulatory effect. So

Essentially, by trapping blood in the tissue and then releasing that pressure, you get this fast ejection of blood, which then ultimately increases it dilates the blood vessels, which forces more oxygen back into the tissues and gets the circulation going. Due to that, if you do that on a flight, you're going to remove the lymph, you're going to remove the the damaging free radicals that are built up on that flight. So you're helping tissues be more prepared for when you land.

So that's an incredibly effective strategy, an incredibly important one because for the team who doesn't do that, you're turning up more fatigued. And you can see that in HRV markers, you can see that in sleep quality. When you do something like Hydro on a flight, we're improving those things. So yeah, an example there for travel, it's it's incredibly important to do a circulatory flush.

Richard Graves (06:01.478)
That's really interesting because we talk about the compression, if you like, of a tournament schedule of this nature. And I suppose you've got to be acutely aware as well of finding the right time to use a tool such as BFR without increasing the unnecessary psychological stress on an athlete because as we keep saying, every second, every minute, every hour matters.

Warren (06:23.589)
Yes.

Warren (06:29.085)
A hundred percent. I mean some of these athlete all of these athletes it's kind of the pinnacle, right? I mean they may be playing for some of the best teams in the world, but to represent your country is you know, it's it's top of the rung of the ladder, right? So these guys are and and ladies

Not this World Cup of course, but the these guys are looking for every single element or stone they can turn over to improve their readiness, their availability, their performance. So yeah, st tools and strategies like blood flow restriction have come to the forefront in the past decade, I would say. Because when you're at such a high level and high capacity, you know, high performance has never been higher. It's never been more exceptional. So we're looking for these one percenters to essentially take us that little bit further. And blood flow restriction is

something that does and delivers several percent more because it can be used in a multitude of ways. So yeah, I think what we're seeing is this transition into enhancing circulatory benefits for athletes as the new thing in sports and you'll see much more of it in the coming years.

Richard Graves (07:29.422)
So in this context then, Warren, I wonder what a meaningful BFR session looks like from things like cuff pressures to timing and the natural training schedule during game to games, which might only be three, maybe four days.

Warren (07:45.754)
So the the protocols flex to suit the demands and needs o of your team essentially. So for example, if you look at the Socceros on their Instagram, they've posted some really cool content of using Hydro in the C.

That was never a gold standard protocol from the literature because no one's ever done that before. But what they've done is paired very nicely a cooling strategy in the heat with a circulatory enhancer with BFR and while having fun. So that's a really innovative way of saying we know the science exists, we know it's beneficial, we don't yet have a gold standard protocol for the use in the sea because no one's ever done it.

But we're going to rely on the science that exists and deploy our own strategies. And they were doing three loss of five minutes application with two minutes flushing in between.

And I will say, in a shout out to Belgium from back in the Qatar World Cup in 2022, they were the first people that I'm aware of ever to use BFR in the water as a squad-wide recovery solution. Again, for a similar purpose, but that was in a swimming pool. So what we're seeing is people understand the benefits of BFR, and what they're trying to do now is fit it to their environment to make sure it's easy and sequenced through their current flows.

Richard Graves (08:59.15)
Obviously players are going to get injured in a tournament of this nature and there will be an increased pressure on trying to get them fit and match ready as soon as possible because time is of the essence and you need them to be performing on the field. I wonder in the context of BFR, in what forms can that be used to help bridge the gap if you like between rehabilitation and being match ready and what forms, what shape does that take?

Warren (09:28.453)
Yeah, I guess it obviously depends on the nature of the injury. You know, if it's if it's a low grade, then fine, we can we can definitely use some blood flow restriction for a short turnaround. If it's of a serious nature, they'll be pulled, of course, and there's nothing we can really do at that point. However, with that said, if you have kind of micro-tears and damage to the degree it will only take a week to heal normally, you can expedite that with BFR because what we're going to do.

Is essentially force blood into those into those tissues, force nutrients in there, glucose, amino acids, we're gonna force oxygen into the tissues and really just put it in a state or environment that's highly conducive for recovery. So again, what they would do is potentially doing some BFR walking. So throwing on the shorts, strapping in, going for a walk, the load on the tissue is low.

But the physiological changes are high, so we're getting a real magnified impact there. So it's a very useful tool in the acute stage of a low-grade injury to get them back much, much quicker. But also I think an important point to make is what about athletes who aren't injured and touch wood, they don't get injured, but

priming them or preparing them so they don't get injured, protecting their tissues. And that's one of the most widely utilized ways at the World Cup using blood flow restriction actually. So it's in the priming, in the warm-ups. So you'll have seen you may have seen some of the content of England football, obviously using mobility drills in the fields and they will add some hydro to that. And the reason for that is again just dosing those tissues with additional oxygenated blood.

to ensure that they're robust, to ensure that they're primed and ready to perform so that the injury risk is lower. So we're not just trying to recover from injury, we're trying to mitigate injury as well by dosing circulation.

Richard Graves (11:15.746)
We've spoken a lot about how practically we use BFR and what forms that can take for these athletes. But as you'll be all too well aware, given your background, Warren, increasingly professional sport, elite level sport is a data driven industry and coaches, practitioners like statistics and numbers in front of them. So when it comes to blood flow restriction therapy, what tools do you tend to use? What are you finding?

to be the most effective in the field and what are the sort of results you're seeing.

Warren (11:47.236)
Yeah, so because we have an analog device without any data attached to it in real time in terms of screens, we've we've gone a different route. So we've actually done all of the validation behind it and done the research to prove the numbers so that when you get to game day or preparation or recovery, whatever it might be.

You're already safe in the knowledge that this works within this this range of numbers. And because of that, we can green ticket and just focus on the thing we need to focus on. We don't need to focus on numbers, we need to focus on consistently applying the technique to drive the outputs that we want. We've actually just published a really, really interesting paper. it's called what's it called? It's a point-counterpoint discussion on arterial occlusion pressure.

So in the industry for many years, people have been prescribing very specific pressures for blood flow restriction. And what's happened in more recent years, as BFR has been more widely accepted and adopted, we found that to be a barrier because if you're trying to look for a specific number, it means you can only use it with one athlete at once. So it negates the ability to use it across a squad. And it means you probably have to supervise them, which means you can only use it in a clinical setting. So what we have done is we have built in pressures within a range so that

You will always be within a safe and effective zone of BFR. But now you can put that to the side and say, okay, now where can we apply this? Is it in a swimming pool, in the sea, in an ice bath, on the field? We can go running with this on. You know, we can use it anywhere because it's more practical. So numbers are important. I will underscore that, but only to a degree. If it impedes practice, they then obviously are kind of a hindrance as opposed to a positive.

Richard Graves (13:27.276)
You realise what you're saying there is bucking the commonly accepted trend when it comes to sports science at the moment because people, coaches, managers like simplicity. They like routine. They like having, for the sake of a better phrase, spreadsheets in front of them. Given what you're saying, that it seems to be more organic when it comes to BFR. Have you encountered misunderstandings, misconceptions then? if so,

How do you ever come?

Warren (13:58.756)
I do think the industry is is evolving at the moment. So it it went very, very data led. And I remember when I worked in the Premier League, it was

A thousand different data points and we'd only use three. It was paralysis by analysis. And I have seen that start to change because of conversations that I'm having and other people in the industry, many people are, around the practicality. As long as we trust the science, are we actually able to use something consistently? If the answer is no, then the the very heavy kind of regulator prescription is a hindrance, essentially. Because muscles don't count, they experience a signal. It's as simple as that. As long as they're being triggered for

So you are correct in that at the beginning there was a lot of scepticism. There was a lot of where are the numbers behind this? So we went and did the research and provided the numbers. Then the next question is, well I want it in real time. Okay. So we've then educated as to why you don't need it real time. And now this paper's been published on the point counterpoint argument. For the record, that's with Jeremy Lenickey, Luke Hughes, some of the world leaders in BFR, and we've agreed that for practical use of BFR, we don't need highly specific numbers, we need regulated ranges so that we know it's safe and effective.

So that it can be used in the field. And we're seeing that happen more and more in professional sports and the conversations I'm having with coaches, whereby practicality and consistent use of any modality is actually more important because if it's too highly prescribed and you can't even do it, what's the point? What is the point in leaning on a research paper that you can't apply?

Richard Graves (15:29.036)
Yeah, absolutely. And given some of the teams that in this World Cup that are now implementing and using blood flow restriction therapy, it would suggest it's an argument which you're beginning to win. Now look, of course, within a team there are individuals and you've touched upon it earlier in this conversation, Warren, that each individual is different and therefore will require different adaptations when it comes to training schedules, methods and yes, BFR.

How do you tailor it then to suit the individual's needs?

Warren (16:01.475)
Yeah, I think what's been interesting at this World Cup, so I'll give England as an example, most of the players have already used Hydro in their club, in their club setting, in the Premier League or otherwise. So they Yeah, they've they've not come to this blind. It's it's something that they're very well accustomed to. And while you'll never get 100% client compliance for any modality at all, we're finding that because these are the kind of creme de la creme of athletes, they probably are

Richard Graves (16:13.08)
so they're familiar with it.

Warren (16:29.347)
the greater adhering athletes in their team setting, and therefore when they come to the World Cup, they're more likely to use Hydro anyway. So

We found that to be a huge benefit. And that's just time in the market. That's just time educating people and people getting to feel their best use cases with a product. However, you will find differences in how people apply it. So in the literature, there are prescriptions, there are modalities that are best known. But again, going back to that point that muscles experience a signal, it doesn't necessarily overly matter if you're highly prescriptive or actually just that you're actually doing it. So for example, some people do three lots of five minutes.

Of BFR with two minutes reperfusion in between. Others do three lots of three minutes. The reason is their recovery protocol at their team setting has lent itself to fit that timing. So they actually adopt that and they still feel really good. There is no gold standard at this point that I'm aware of in BFR. It's only that as long as you do it, as long as you do about three rounds and as long as you accumulate enough stress and release that pressure, you're going to drive an impact. So

Yeah, it is highly individualized, but it's also very flexible to meet the individual's needs. And one final point I'll make on this is we're very, very heavy on supporting coaches and athletes, particularly at the World Cup as well. So we've set up WhatsApp groups with every team, all the coaches. So we'll provide knowledge and insights every other day. We'll check in with them when we see a game. We might see a niggle, and we'll be like, Okay, use this protocol. We'll send them bespoke personalized protocols to send to the lads in WhatsApp groups again. So we we're not just

selling our products. We're here to support them with best use case for leveraging blood flow and improving their circulation to drive outcomes.

Richard Graves (18:14.574)
Of course, sports science as a whole is constantly evolving and just from what you've said there, clearly BFR, its application, our understanding, that continues to evolve now. I wonder, given your interaction with the clubs implementing it over the course of this summer's World Cup, is it actually evolving during the World Cup?

Warren (18:36.227)
The use of blood flow restriction. I think what we're seeing is so there's been years of accumulated use and there's lots of really cool innovation going on at clubs. But because this is the world stage, I think we're seeing that come to fruition and people are seeing it more visibly.

And I think what's really cool is knowledge sharing that I'm seeing at this this year's World Cup. I'm speaking to coaches who were speaking to one another from from opponent opponents and other teams. And it's really quite refreshing. There are in fact I've got a really cool story to share. This is last World Cup in Qatar. So USA were using the product as were Belgium and a couple of other teams. And there was an issue with some of the products arriving to the Belgian team, or they'd misplaced half of their product. So

I put them in contact with Belgium, who had a surplus of stock. They went and met at the embassy. And that was amazing to see that they were collaborating and sharing products, you know, to support the team. But what happened was at the embassy, Rick Cost, who was from the USA picking up the units, he was sat there in a car for ages. So the guys with the guns come out and they were like, What are you doing here? Like you're skulking around, this is really unusual. So I got him just picking up some products, but the Belgian team hadn't turned up yet. So he was there for several hours. And I spoke with him about this on a podcast a couple.

couple of years ago he said he was really embarrassed and worried about these guns in his face essentially. But that's a good example of sharing, you know, teams who just respect one another and are happy to not only share knowledge but share products. That that was an incredible, incredible insight.

Richard Graves (20:08.418)
And it's an acceptance as well, an open acceptance that this particular method is working, they can see an impact it's having both on the individuals and the team as well. And once you get them buy in, as with anything from professional athletes, that's the tipping point, isn't it?

Warren (20:25.645)
100%. I think at the beginning of this journey, we were very much focused on selling the, you know, the problem, the solution to a problem that they had.

Without being cognizant of everything around it. So you know, things like the politics in that particular club, what's going on at the moment, has a manager been fired? Is there a bit of tension? have they got a real, I don't know, disparity in the team where there's a senior leadership group, there's young players who aren't really adhering to it? What is the environment like? Not just does your product solve a problem, because if you're not cognizant of everything going on, you're not going to be able to sell the product in because there's so many barriers to that sale. So what we've been amazing at in recent years is

Is really getting to know the coach and their group of coaches and athletes to understand their environment. Because then we can have visibility on how we can actually help them, not just flogging them, this is great for recovery after a game. Yeah, but what about if they can't use it after a game for these three reasons? We weren't aware of that. So yeah, I think that's been one of the massive learnings for us as a business in the past few years. It's just a a more overarching view of what's going on in that particular team.

Richard Graves (21:31.244)
Well, having a more overarching view, there are a few better opportunities to increase the scope of that than a competition like this World Cup. So I'm going to give you a hypothetical now before we go. Warren, you have unlimited resources. You're able to conduct the largest scale study when it comes to BFR that you have to date. What is the one question you would want answered coming out of what we find in this World

Warren (21:42.04)
Okay.

Warren (21:58.724)
Ooh, that is a fantastic question. So I think with the way the world's going, and AI driven, data driven, as you said, but meaningful data, let's let's underscore that. If everyone had some kind of wearable, I won't name any particular sensor, I would love to know over the course of the World Cup, if every single athlete had the same sensor and a pair of hydro shorts, and we could standardise their usage.

what happens to their HRV kinetics, their sleep quality, their recovery scores, and basically what's what happens what happens to their physiology from using Hydro across the top elite competition. We do have insights of this from our work and research with companies like Whoop, and we're actually going to Adidas tomorrow to do some more research in Nuremberg.

But unlimited resources, that will be every single player or every single team doing that type of research over a longitudinal period. And no one could question the validity and the reliability and the benefit, I guess, of Hydro at that point with that data set.

Richard Graves (23:05.738)
I'm sure in the aftermath of this World Cup, we'll certainly see some studies, some research, some results come out. Whether it comes out on that scale or not, maybe that's one for four years from now. listen, as always, Warren, it's fascinating getting into this with you. For our listeners, where can they find out more from you and Hytro on social media?

Warren (23:26.585)
Sure, just head to Hytro on Instagram or Dr Warren Bradley or on LinkedIn. We're posting some really cool insights. Again, just Dr. Warren Bradley or Hytro. And finally, just head to the website. There's plenty of incredible blogs and and guests, podcasts, etc. And that's just Hytro.com.

Richard Graves (23:42.39)
Absolutely will be checking that out. Thanks once again for your time.

Warren (23:45.453)
Thank you very much, Richard. Great to speak again, buddy.