The adidas UltraBoost 21 signifies a revolutionary (and extremely comfortable and energy returning) step in the development of the iconic franchise. But what goes into a redesign like this and how can it benefit your game?

The adidas UltraBoost 21 boasts six percent more Boost foam in the midsole than its predecessor, alongside a newly redesigned torsion system known as adidas LEP (‘Linear Energy Push’), which provides a 15 percent increase in forefoot bending stiffness for a more responsive stride. In short, it’s a new experience in running, and Sam Handy was integral to its development. That name may well be familiar, and that’s because his previous role was as Creative Director of adidas Football, where he was responsible for – among other things – the return of the Predator.

So how did his knowledge of the football arena influence the design of the UltraBoost 21? And how will this new trainer benefit footballers? We spoke with Handy alongside adidas Design Director, Moritz Hoellmueller to get answers to this and to get more of an insight into the shoe’s development.

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How does your background in football influence how you work on a shoe like the Ultraboost? Is there anything you’ve carried across?

Sam Handy: I found that working on football products really makes you always consider both the functional benefit of a product and the ‘boldness’ of its visualisation. Our boots are worn by the greatest players in the world, so they have to perform (and stay performing) at an incredibly high level, but they also need to be visible across a 90,000 capacity stadium and on TV screens across the planet. I think you see us bringing this approach of combining function with bold simplicity in recent launches like adizero Adios Pro and UB21.

How different is the process from designing a football boot to designing an Ultraboost iteration? 

SH: Functionally the sports are totally different so the insights and ingredients that power them don’t have much overlap. What unites them though is the process of building the best product, for the best athletes with incredibly demanding testing and quality. Also, both football and running are critical to the credibility of the brand in general.  Shoes like Predator or Ultraboost ARE adidas to a certain extent so they need to express the brand essence as well as deliver on its performance credibility.

What performance benefits does the Ultraboost 21 have for footballers? Especially with a season so unique like this where it's so start stop...

SH: We’ve all seen athletic ‘fitness’ match game sense and ball skill on modern pro players.  You need a lot of endurance to perform well through 90 minutes and a shoe like Ultraboost would be a perfect way to complement your on-pitch training.

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You need a lot of endurance to perform well through 90 minutes and a shoe like Ultraboost would be a perfect way to complement your on-pitch training"

What are you most proud of with the Ultraboost 21?

Moritz Hoellmueller: For me, the best thing is the incredible and diverse team that we have at adidas that brings these concepts to life to create products that we truly love and believe in. A shoe like this takes around two years from concept to execution, so there is a huge number of people that come together to make it all possible. It’s amazing to be a part of that journey.

What do you feel is the key performance benefit of the Ultraboost 21 over the previous version?

MH: We would say that Ultraboost 21 is our most holistic BOOST shoe ever based on the updates and improvements that we’ve made from all angles.

Not only have we optimised the BOOST by 6% compared to Ultraboost 20 to provide greater cushioning, but the adidas LEP increases the forefoot bending stiffness by 15% to give a more responsive ride. The PRIMEKNIT+ upper is also a more precise knit designed and forged for incredible support and enhanced movement, combining pure comfort with lightweight performance.

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Are there any technologies players might recognise from their boots? Is football influencing running, or vice versa, or a bit of both?

SH: The one request from athletes across all sports is for comfort alongside performance.  That’s why you see PRIMEKNIT uppers across both running and football. It’s the most comfortable footwear possible.

How would you suggest runners include Ultraboost 21 in their rotation and what are your most complimentary shoes to use alongside it?

MH: Ultraboost 21 is the ultimate experience of comfort and responsiveness and gives every runner incredible energy. Ultraboost 21 is an extremely universal shoe designed for runners of all shapes and performance levels so it can be used for all kind of different runs.

How were the claimed improvements in energy return measured?

MH: Ultraboost has always delivered great energy return and Ultraboost 21 is no different. The incredible energy return that Ultraboost 21 delivers really comes through all of those improvements outlined above. 

During the development of the shoe, we looked into the level and the amount of BOOST that you have underfoot, to give a very soft and transitional feeling when the heel strikes the ground. This then gives a very smooth transition through the rest of the foot with the adidas LEP creating a spring effect through the forefoot that gives a more responsive ride.

Are you seeing a lot of requests from footballers for pairs when it comes to pre-season?

SH: Yes, and I’m sure you will see a lot of pro players in UB21 in the coming months.

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The one request from athletes across all sports is for comfort alongside performance.  That’s why you see PRIMEKNIT uppers across both running and football. It’s the most comfortable footwear possible"

David Beckham was involved in the feedback process. How useful is his input? And is he still always excited to see and try new innovations?

SH: David is a great and long-standing ambassador for our brand and is also a very keen runner, so it was natural for him to be a part of the Ultraboost 21 campaign. It’s not just David though, we’re also lucky to have the support across our whole athlete portfolio, including the likes of Olympic 400m gold medallist Shaunae-Miller Uibo and World 200m Champion, Noah Lyles.

Does the success of the series pile on more pressure to design the next version of it? Similar to when you were tasked with designing a Predator for example?

SH: Absolutely. ‘Rebuilding’ isn’t only the functional challenge of building a better shoe that something that was already amazing. It’s the ‘pressure’ of changing something that so many people love.  Ultraboost is the same.  It’s one of the greatest products that adidas ever built and we have a lot to live up to every time we update it.  I hope you see in UB21 that we have really considered all the ingredients that made so many people fall in love with UB15 but have maximised the experience they deliver so that you can fall in love all over again.

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The adidas UltraBoost 21 will be available from from 4 February.