Professional cycling’s off-season is the time for atmospheric drone shots from Calpe training camps, much online sartorial comment on kit launches, and the latest transformative collaboration between team and revolutionary training tool, the majority of which fly under the radar.
But one piqued our interest in mid-February when the press release came through that, “Hytro, the pioneers of wearable Blood Flow Restriction (BFR) technology, used by over 200 professional sports teams, are thrilled to announce an exciting new partnership with Soudal Quick-Step cycling team. This marks Hytro’s first step into the world of cycling and underscores the team’s commitment to integrating cutting-edge recovery methods into their training and race-day routines.” Which is why I’m typing this in a very, very tight pair of shorts.
I’d heard that the likes of Messrs Messi and Ronaldo were BFR proponents and now it was publicly entering the cycling domain, but was there real science behind this rather restrictive technology or simply marketing money? And if it is of use to the likes of Remco Evenepoel and Paul Magnier, does that transcend to the recreational rider? Time to squeeze out an answer…
Established rehab regimes
First things first, while Hytro’s official involvement at WorldTour level might be new, the field of bloodflow restriction very much isn’t. The BFR technique originated in Japan in the 1960s when Yoshiaki Sato self-experimented, using BFR to rehabilitate from a fractured left leg. Since then, swathes of research in the medical arena has supported the use of BFR in a medical setting, the idea being that by restricting, and then releasing, blood flow through the limb, you create a stress and pressure that results in a cascade of outcomes conducive to accelerating a return from injury.
These include cranking up growth-hormone release and type-11 muscle fibre activation to drive muscle growth; what’s termed an ‘increased vascularisation of the tissue’, meaning your muscles can receive more oxygen for faster recovery; and increased heart rate for a cardiovascular fitness boost. In a rehab setting, BFR has also been linked to strengthening bones and ligaments, and it can be used both when sedentary and during easy exercise.
“The primary reason I use BFR is to rehabilitate an athlete when they’re sensitive to mechanical load. For instance, if they have anterior knee pain and are struggling to take weight,” says Bianca Broadbent, consultant physiotherapist and bike fitter. “One of the benefits is that you can exercise with a stimulus despite being injured.”
Rapid recovery?
So, it’s established that BFR is a common rehab tool. Where the field and research is evolving – and arguably where WorldTour teams are tapping into its benefits – is in a recovery setting. As recreational riders we know how important recovery is to not only optimising the next ride but coping with the busyness of life in general. Impaired recovery equals perma-crankiness and ultimately divorce. For professional riders, it can be the difference between victory and defeat, a new contract or seeking a new career, especially at Grand Tours where it’s all about racing, eating and recovering for the next day’s battle.
That, according to Dr Warren Bradley, is where Hytro comes in. Bradley is Hytro’s founder. The Englishman has a glittering academic and professional CV. He has a PhD in exercise physiology and nutrition from Liverpool John Moores University. He’s also been head of performance nutrition for a host of top sporting clubs including Munster and England rugby, plus Hull City and Derby County in football.
“It was in this club setting that I came across the BFR technique,” he says. “I could see it’d been used in rehab for decades, but there was also evidence extolling its benefits on recovery. Professional sports(wo)men regularly use massage, ice baths and compression wear. I was thinking, why aren’t we using this in a recovery setting?”
The answers were numerous, but the primary one came down to the traditional method of creating occlusion (a complete or partial blockage of a blood vessel) involving inflatable cuffs that required medical supervision.
“That’s why I set about creating a scientifically proven product that delivers the recovery benefits in a wearable that you can use without supervision,” says Bradley. “The results are shorts for the legs and a t-shirt for the arms.”
Naturally, it’s the shorts that they’ll be using at Quick-Step and, as I can testify, they’re simply used. Each leg features a strap that you pull tight around the inside of your thigh and Velcro down on either ‘1’ for moderate pressure or ‘2’ heavy pressure. Then, beyond initially feeling like you’re in line for medieval amputation, let the physiological magic happen.
“When you apply the pressure and restrict the flow of blood, you get swelling in the muscle tissue,” says Bradley. “The cells swell with blood and when that happens it triggers a hormonal pathway called ‘muscle protein synthesis’. That's crucial for both training adaptations and for recovery as it’s the central regulatory pathway for your body to adapt. You stimulate accelerated muscle repair.
“Then, when you unstrap, you enjoy a powerful ejection of blood that removes inflammation and waste materials. If you’ve been riding for five hours, you’ve generated excess lactate and metabolites. They’ll be screaming at you but Hytro flushes them out.” This extreme flush, adds Bradley, is one of Hytro’s key sells; that its simple strap and unstrap design results in a greater, more immediate rush of blood. That’s not all.
“In theory, you can also accelerate the nutrients from recovery fuel into your body, too,” he adds. “We know fresh blood is dragged into the tissues and forced into the cells. That’s why if you have a recovery drink after a hard ride, slip into the shorts and apply the pressure, you’ll potentially drive more nutrients into the cells and your tissues will recover quickly. It’s essentially leveraging the body’s natural processes and dialling them up.”
Fast-tracking your carbohydrate-and-protein drink into tired muscles sharpened our fatiguing minds, but we couldn’t find research on this particular benefit. “It’s probably more a working hypothesis,” says James Spragg, coach and sport scientist at Tudor Pro Cycling. We’d heard on the sport-science grapevine that Spragg was a BFR proponent and, just as I was about to file this piece, Spragg confirmed that Julian Alaphilippe’s team are now using Hytro in an official capacity. “I’m not aware of scientific studies that have assessed nutrient delivery to the muscles. That said, in principle it’s a similar idea to a cool-down whereby the aim is to clear out metabolites and drive in nutrients faster. Research into recovery is increasing but isn’t as deep as in the rehab field due mainly to having to use BFR in a supervised setting.”
The appeal of Hytro to the likes of Spragg and Quick-Step is its stamp of approval – more precisely, ‘scientific validation’ – for unsupervised and everyday use. It’s the first time a wearable’s been given the lone-wolf BFR thumbs up, meaning the sight of Remco nipping off to his team bus to slip into his tight shorts, before mainlining recovery foods and ticking off media duties could become a common one.
Amplify training gains
That’s not all. There’s a third and final area whereby BFR piques the interest of professional cyclists and that’s training. “It’s really an evolution of the rehab work, which is around accelerating hypertrophy in a limb enduring atrophy,” says Spragg. “First, it was expanded in a strength and conditioning setting and then we started thinking about endurance-training application.”
One of the key drivers behind its use in cycling was Dr Conor Taylor, coach at Ineos Grenadiers for many years before being part of the Ineos exodus in the off-season. “His PhD was on the augmentation of exercise using BFR,” says Spragg, “so in that space, we have increasing evidence it works.”
Taylor showed that BFR intensified the training stimulus, inducing exaggerated physical adaptations that are endurance gold, like increased capillary supply and mitochondrial function, both delivering the fuel to ride higher, faster and stronger.
Spragg says there are two main methods of BFR use in training. “Basically, in an interval session, you can occlude during the work bout or the rest bout. In Conor’s PhD, the subjects undertook high-intensity exercise, sprinting for 30 seconds. Then they whacked on a blood pressure cuff, occluding the muscles, which ultimately heightened adaptation to the stimulus. It’s quite painful but does seemingly work. And at this level, it’s all about maximising that stimulus as there are few gains to be had.
“You can also use it during the work bout, albeit that’s often more about the rehab side, like if a rider has a knee injury and can’t take too much load. So, you’d get them on a static bike, ride at a low intensity and occlude during the work efforts. Typically, we’d have them riding at 30% of what they would do normally for high-intensity and repeated five-minute efforts. Mechanically, they won’t be ready to ride at 450 watts, but they can cope with 150 watts and enjoy a similar metabolic stimulus.”
A unique rush
It seems that BFR is the omnipresent training tool that you never knew existed. On the UK scene, coach and physiologist Alex Welburn has been using BFR for years, albeit predominantly with inflatable cuffs. He’s currently studying a PhD at Loughborough University in the field of cycling power. He says he uses it in a similar manner to Spragg and has used it extensively with track riders with the aim of improving critical power. He sees its benefits but cautions that it’s not the most pleasant gain to be had.
“In terms of sensations, it’s hard to describe,” he says. “Some feel the need to be sick when the cuff is deflated, some even are. It’s a ‘rushing’ feel, so it’s not the most comfortable of feelings.”
That’s the cuffs, which must be under supervision. What about the payback when slipping into the tight Hytros? “It’s similar to when you have your blood pressure taken, as it’s a strong circumferential pressure around the top of the limb, albeit I’d say it’s more comfortable because of the soft material,” says Bradley.
“You’ll feel the swelling and feel the stretching in the tissue as it fills with blood; you'll feel very minor tingling, which is the oxygen being reduced in your muscle tissue, so hypoxia. You might feel numbness, like you might when cycling hard and pushing yourself into a hypoxic state. If you've got light skin, you’ll see discolouration because your limb’s filling with deoxygenated blood. That’s normal.
“But it’s safe. We spent a long time iterating the mechanism to make sure it was safe for everyone. Professional and amateur athletes alike can use it. I mean, even NASA have used it with their astronauts.”
As for my experience using post-indoor rides, once I’d overcome feelings that fluctuated between masochism, concern and confusion, it soon became the relative norm. How much it helped to improve my performance is hard to quantify as my brief guinea pig stint coincided with a surprisingly painful broken big toe, which tempered things somewhat. I endured no lightness of head, albeit I stuck to level ‘1’ not the tighter, more pressured ‘2’.
Recreational user
Should the everyday cyclist use BFR? Broadbent has reservations from a safety perspective in however you dress it up, you’re looking for arterial restriction and venous occlusion (tourniquet). “Certainly, when it comes to occlusion via cuffs, BFR’s calculated on limb occlusion pressure or LOP,” says Broadbent. “Then you’d work at different percentages of LOP, which is user specific. This is all done under supervision.”
But, she adds, this is a different occlusion technique to that of Hytro, which, as above, has been given the scientific validation to use unsupervised. If you’re into your LOP pressures – you never know, some of you might be – Hytro say that, “The highest setting on the Hytro shorts exerts a maximum pressure of 190mmHG, which creates a partial occlusion of between 60 and 78% LOP, which is well below full 100% occlusion… There is no universally agreed optimal %LOP, and it will change from user to user, but aiming for 60-80% will put you in the optimal operating zone as identified by multiple studies.”
To hammer home the safety aspect, Bradley says that there’s no evidence of greater risk over other exercise modalities. “That said, like with any exercise, there are of course contraindications to be aware of,” he says. “Those conditions include blood clotting disorders, vascular issues or severe hypertension, as pressure applied could exacerbate these issues. And if you become dizzy, stop immediately. As you would with any exercise.”
What’s important, from a rehab, recovery, performance and safety standpoint, is that you follow the correct protocol. “No more than around 15 to 20 minutes is optimal because, like all training, there’s a ceiling of what you should do,” says Bradley. “Protocols can vary but as an example for recovery, we’ve simplified it to three rounds of five minutes of BFR. So, that’s five minutes strapped in, two minutes off, done three times.”
Again, we come back to the question of whether it’s for you? Granted, the thought of occlusion might not be your bag and, like most avenues to improving performance, it’s not the most comfortable. Hytro’s ticked those safety boxes, but is it worth the spend or simply a tool that your level of cycling doesn’t warrant? A marginal gain when you’re better off focusing on the maximals?
“I’d say there are potential benefits but it’s very much an individual thing,” says Spragg. “If you’re a keen and time-starved amateur who only has 30 minutes to exercise once the children are in bed, would you benefit more by adding BFR on top? Potentially, yes.” It’s clearer cut at the professional level, Spragg adds, where you’re looking for the most minor of gains for a competitive advantage.
Ultimately, whether you add BLR and Hytro to your training arsenal is down to you, your ambitions and how receptive you are to potential scientific developments. And whether you’re happy to restrict your blood flow and the discomfort that comes with it. If you’re a convert or not, you can always just sit back and see if Remco can squeeze out his first Tour de France triumph… Ouch.
