'They're not just race shoes', Nike's VP of Footwear Innovation says of the Alphaflys

Jane McGuire
Photo credit: Kevin C. Cox - Getty Images

From Runner's World

When we sit down to chat with Tony Bignell, VP of Footwear Innovation at Nike, it doesn't take long before we address the elephant in the room - Kipchoge's shoes. "But did they have three plates?" we ask. Bignell laughs and shakes his head, "his shoe only had one plate, it’s exactly the same as the Alphafly in front of you".

We're here to talk about the Alphafly, but our interview happens less than a week after the new WA rulings, which imposed an immediate ban on any shoe with a sole thicker than 40 millimetres (mm) or shoes that contains more than one plate. Bignell is keen to discuss what this means for the brand and the shoes of the future with Runner's World, plus, the secrets behind the shoe that broke the two hour marathon.

Let's talk about the Alphafly - are they Kipchoge’s shoe and if not, how are they different?

Yes, the Alphafly in front of you is the same basic build up of the shoe he wore. Some of the confusion around his shoe is down to some of the patents we filed around the same time. As a brand, you have to file patents for the future and the rule is the first to file. We file a lot of patents because we’re trying lots of different prototypes all the time, so people see a patent and they associate it with a shoe and those things aren’t necessarily true.

So his shoe had the one carbon plate?

His shoe only had one plate, it’s exactly the same as the Alphafly.

And it wasn’t higher than 40mm?

The ruling is based on a sized 8.5. Eliud’s foot size is bigger than an 8.5, but the ruling is 40mm at a size 8.5, so a woman’s 6 is a lot smaller than 40mm and men’s size 15 would be a lot bigger than 40mm. That’s just normal - every shoe does that. So, his shoe might measure taller than 40mm, but that’s not the ruling, the ruling is in that model, at that size.

Photo credit: Nike

You’ve said the shoe is legal, have you had that from World Athletics or do you need to wait?

No we have to wait. The ruling just came out on Friday, but as we understand it, when you look at the rulings and measure a men’s 8.5, the height between the ground and the top of the sock liner is less than 40mm and it has one plate. So we’re very confident but we’ll wait and see - we are here to respect the rules.

As an innovator, is it disheartening to have these new rules as a barrier for the future?

On one hand, it’s a vote of confidence that people are talking about it because we feel like we’re making a difference and that’s what we’re trying to do. But on the other hand, it is a little bit limiting and I personally think that the line should be whether you’re giving the athlete more energy back than they put in, that feels like the guideline. With all of these shoes you don’t get more energy back than you put in. In a regular running shoe you’d land and lose 30-40% in heat and movement and we’re just trying to make the shoe more efficient. I’d love to get to 99.9% efficient and once you go over 100% that feels like you’re cheating, but none of these shoes are anywhere close to that, we’re just making them more efficient than they have been in the past.

Let's talk about the design of the Alphafly - what have you taken from the learnings of the Next%?

This shoe has just been a continuation from the Next%. All we’ve done really is look at where the athlete needs the resiliency and responsiveness the most and it’s really in the forefoot, that’s where you create most of your power and effort and energy. We took out the foam and replaced it with the more resilient material, which is Zoom Air so that’s been the focus and that’s the biggest difference.

Photo credit: Swanson Studio

What do the Air Pods bring to the shoe?

If you look at general foams, they return 60-70% of your energy back, the Zoom X foam returns about 80% of the energy back and Zoom Air returns about 90%, so we’ve just taken out something that gives you 80% and replaced it with something that gives you 90-ish%. So you’re just making the system more efficient, more effective.

I've been lucky enough to jog up and down this space in the Alphafly and the shoe almost rocks you forward - I'm guessing this is intentional?

Absolutely intentional, I think that is the carbon fibre plate which acts a bit like a rocking chair, it just guides you through and up to that position where you want to be pushing through the floor to give you the most effective position to do your next footstrike. It’s a combination of the foam for cushioning, the plate which rocks you into position and the zoom air bags which really propel you and protect you for your next foot strike.

How many miles do you think they’ve got in them?

I think they are really similar to regular running shoes - every shoe is different to every different person, depending on how your foot strike is and how you run, but often people will say 400 miles is an average.

So they’re not just a racing shoe?

They are absolutely not just a racing shoe - the foam is proved to work over hundreds of miles. We’ve had hundreds and hundreds and hundreds of miles tested in this shoe. So no, it should be as durable as any other shoe.

How important is athlete feedback - Kipchoge broke two hours in these shoes, did he come back to you with feedback, did you tweak things?

We’ve tweaked this hundreds and hundreds and hundreds of times, specifically with his feedback, but also his training team - we’ve had hundreds of male and female athletes in these. Eliud is amazing, he’ll handwrite notes for us, we’ll meet him many times a year, we do face calls, we have his information every single day for every single run. There’s a constant dialogue to make us better and his standards are super high which is great - it really helps us.

You've also launched a new training shoe - will that be legal?

Under the regulations, that is not legal because it’s higher as there’s more foam in the shoe. We didn’t know the regulations when we made this shoe, but the reason we added more foam was to give the athlete more protection. It’s a little bit counterintuitive - we haven’t done that to make an athlete faster, we’ve done it to make them more protected. I think we need to understand how the rules get enforced - is it the people who finish on the podium or receive money, or just anybody who runs the London Marathon - I think they’re very different.

What did you envisage coming next for the Alphafly and will this be put on pause in light of the new regulations?

We’ve been working on the next one for a while because that’s just what we do, so now we’ll reflect on where the regulations are because we want to respect the rules. Our job, like I said before, is to try and close that gap to make athletes more and more efficient. It’s about three things - trying to protect an athlete with cushioning, trying to propel them forward and trying to make the shoe light. When you look at the Alphafly they don’t look light, but when you pick them up, they really are. Personally, I think there’s something about the 'right weight' for a shoe - the right weight on the end of your body that is heavy enough to protect you, but light enough so you can run fast. It feels like we’re getting close to that kind of good balance.

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