The Future of Super Shoes

JARED WARD

In 2018, a week before I was about to run the New York City Marathon, I got a call from Saucony that they had a prototype ready for me. And I said, is this a Super Shoe? They said, yes.

WOUTER HOOGKAMER

I was running more than 40 miles that day. I met up with a group of friends who were doing their weekly run. We ran together. They started to complain that we were running faster than normally. At some point I just started to look at the numbers.

JARED WARD

They sent me the shoes and I ran on a treadmill in a lab measuring oxygen uptake for five minutes. And when I pulled on the last Super Shoe and started running, I thought, this is the shoe. Running just feels easier.

WOUTER HOOGKAMER

This is just a long run at a comfortable effort. And I was just running way faster than I would have been.

JARED WARD

Sure enough, I got off the treadmill and we looked at the numbers and that shoe performed 4.4% on average better than the other shoes. And so I ran New York City Marathon a few days later in that shoe.

WOUTER HOOGKAMER

It just makes it feel effortless and you're going faster than you intend to the way that it should feel. And it's nice.

ROMA AGRAWAL

The running world has been knocked sideways by the development of the Super Shoe. With faster times, new records and extensive research to back up its successes. It's hard not to be tempted by its potential for amateur park runners and Olympic athletes alike. In this episode of Create the Future, we unpack some of the biggest questions left in the lightning bolt trail of running shoes. From how its radical performance is shaped by the latest design and materials in engineering, to the hows and whys of what makes a running shoe so elite. And the question everyone is asking, are Super Shoes fair? Joining me for the conversation are BYU statistics professor Jared Ward, a long distance runner who qualified and finished sixth in the 2016 Summer Olympics, and Wouter Hoogkamer, an assistant professor for the department of Kinesiology at the University of Massachusetts, Amherst, where he runs the Integrative Locomotion Laboratory. On your marks, get set, go.

WOUTER HOOGKAMER

My name is Wouter Hoogkamer. I'm an assistant professor in biomechanics at the University of Massachusetts, and I am a runner and I have been studying running shoes for the past 10 years.

ROMA AGRAWAL

And Jared, tell us about yourself.

JARED WARD

I'm a professional marathon runner. I've run for 10 years professionally and then before that in college and the university system and in high school.

ROMA AGRAWAL

Wouter, can you tell us what biomechanics means?

WOUTER HOOGKAMER

Biomechanics is sort of the combination of biology and mechanics. So we study the mechanics of the human body and there's also biomechanics fields that study other animals or other tissues, but we study how the human body moves. So the forces that the muscles produce, how they go through the joints, and the forces that make us move, and that we have to interact with our environment. So we take a physics approach. We can quantify these things by using cameras to see how people move or force-plates to see the forces they produce. And there's even some imaging technology that allows us to take a look under the skin and see muscle activations or even muscle behaviour.

ROMA AGRAWAL

Sounds a bit like you're studying the structural engineering of the human body, which is brilliant. Now I understand that you run commute. Could you tell us how far you're running and how quickly and what your ambitions are for a potential marathon?

WOUTER HOOGKAMER

Yeah. So when we moved here, we particularly looked for a house in a place that was runnable, distance wise and also traffic wise. So I ended up about six miles from campus and then running is going well. So most often I even take a more scenic detour to make it a nine mile route on the way out. But to be honest, on the way back, I usually get a ride because I also live up a hill. So in the mornings, I would run six to nine miles to work in about seven-minute mile pace. That sort of accumulates. And obviously I'm not as fast as Jared, but I have run a couple of marathons between 2.30 and 2.40.

ROMA AGRAWAL

That's incredible for someone who's just started the Couch to 5K. That's where I'm at. So I'm in a different planet. Jared, can you tell us about what the meaning of the Super Shoe is, and how do they exactly differ from the normal running footwear that I would own?

JARED WARD

You know, we use the term Super Shoe, you know, sort of, I think mostly affectionately for those of us that came from an era pre-Super Shoe to just quantify how amazing the technology is and how much it's changed in the last 10 years. And candidly, Roma, any shoe that you're running in, any running shoe, is beginning to sort of feel some of those technological advances as this technology sort of works its way into what I would say are most mainstream running shoes now. When we use the term Super Shoe, we tend to be talking about a classification of shoes that have incredible foam, oftentimes some sort of plate, whether that's a carbon fiber or a plastic plate, and then a shoe that's maybe shaped differently than we would have shaped shoes 10 years ago. And compared to the class of shoes pre-Super Shoe, research and technology and the pace that shoes got better was essentially a game of trying to make a shoe lighter because science could quantify very distinctively - all things equal - how much faster you would be in a shoe that was lighter.

ROMA AGRAWAL

So Jared, just tell me a little bit about what the difference in your running time might be if you were using, I guess, a normal shoe versus a Super Shoe and perhaps talk a little bit about your experience at the 2016 Olympics, which was so exciting.

JARED WARD

I would characterise a Super Shoe as something that is enabling performance. Whereas 10 years ago, how we improved performance with footwear is we made footwear lighter. Now we're thinking a lot more dynamically. We're thinking about how to decrease energy cost, how to decrease muscle tissue damage. And then on the research side, and particularly some of the stuff that Wouter’s doing and the innovation that they're doing in Massachusetts, how to quantify that measurable difference. But in a marathon for me, as a marathoner trying to make a living running marathons and finish as high as I can in international competitions, these shoes save, I think, minutes off my time. I'm probably two minutes faster in these shoes and running a marathon is less disruptive to my training because my legs aren't as beat up after the race.

ROMA AGRAWAL

So, Wouter, could you tell us a little bit about the science and the engineering of how exactly these work and how they support runners like Jared.

WOUTER HOOGKAMER

Like Jared was saying, historically shoes had been made as light as possible and the foam under your shoe is there for a reason. Like very light shoes were still better than barefoot running. So there's some benefit from running on a soft surface. So shoes were light, but they had some cushioning in there. And then traditional foams had been mainly pillow or wet sand-like, right? So they absorb some of your landing, but they don't give anything back. And then through this innovation, these new modern foams are processed in different ways, developed in different ways, foamed up in different ways. And material science has been able to develop foams that are still soft, but actually they're much less like a pillow and much more like a trampoline. So they return a lot more of the energy that comes into it. Then on top of that, it's interesting that if you have a trampoline, it's even better to have a softer foam, which allows you to put more energy into it and you get more back. Versus if for a pillow, you much rather have a firm pillow so you don't sink in it because it's all going away. So the modern foams are more resilient. They return more energy, more trampoline like. And that allows us also to make them softer. But with the softer foams, you're displacing more. So you need more foam before you hit the ground. So then these shoes start to get taller and taller in the past that was often less than 10 millimetres. Now we see up to 40 millimetres and that's kind of the regulation. There's even training shoes that go beyond that. And then with that foam, the other big innovation that’s much talked about is the carbon fibre plate, which is sort of embedded in that midsole foam. There is biomechanically a lot going on there where the main thing about having a plate in your shoe is that it flexes less around your toe joints when you push off. So normally when you push off, you roll over to your toes and technically, mechanically speaking, at that point, there's some energy lost in your foot for the push off. So putting a stiffer plate there prevents some of that energy loss. But at the same time, if you just put a flat plate in there it makes it a little harder for your calf muscles to actually do that push off. So that's again, where the engineering came in, they found out we need this curved blade and it needs to be sort of under the ball of your foot, and we need more foam to put that curvature in. So that's sort of generically what's happening. Then there is also the curvature probably allows for a better push off. And so there's a lot going on.

JARED WARD

You know, we dove into plates and at BYU they tested various stiffnesses of plates across a similar foam and across the set of runners and essentially confirmed similar conclusions. One, that we don't know everything, but two, it seems that the foam is a much bigger piece of this story than the plate. And as we look at foam, foams are different. We're talking about a trampoline that absorbs energy, stores it, and then returns energy. How long does the foam store energy and what type of interaction between energy storage and returning is necessary for a runner that's on the ground longer or off the ground quicker? And we all have different ground times. I'm a bit of a shuffler as a marathon runner. I have a longer stride, I heel strike. So I'm on the ground a little bit longer than say a runner with a shorter stride that's a mid-foot or a forefoot striker and is bouncing off the ground. So what would be optimal for me is a foam that would store energy a little bit longer than maybe some runner with a shorter stride and quicker step. And so we're starting to get at this idea, and there's a lot of theories around, hey, what do we need to do to be able to cater a shoe to a runner? And the reality is what we've had in the last 10 years is a sort of renaissance for running shoes where the innovation industry has been sort of tipped on its side. We've realized there's more questions to be answered than just weight of a shoe. And we're in a heavy period of innovation and trying to keep up. And so shoe companies are developing and releasing shoes as fast as they can because they're making a difference. World records are being broken. People are running PRs. The qualification times to get into marathons like the Boston Marathon are dropping at a rapid rate because people are running faster. The innovations are happening so fast that the science and research to understand those innovations and to guide them, there's a lot to keep up on.

WOUTER HOOGKAMER

Like technologically, we are probably able to do all this personalisation. We can build a shoe and we can give Jared a curvature in a plate at 90% of his foot length and we can make that plate specific stiffness for Jared and we can give him a slower responding foam with some more stack height. Like the industry can build these things and - maybe not at large scale - individualise everything. But what we already see now is that at least most brands have sort of multiple options. And then if you're an unattached athlete, you have even more options because you can just figure out which brand and which model are best for you. So the research that we do in the lab is all … basically the important thing like Jared says is energy costs. So if we find a shoe and it reduces the energy costs of running, we know that you can run faster with that shoe. That's a big piece of the puzzle. The other thing that Jared mentioned earlier is that his legs feel better the day after a marathon or after hard training. Scientifically, we haven't really seen good work quantifying that effect, but most runners will be aware of it, including myself. So that's another thing that's happening. And particularly when we do research in the lab, we don't have people run a full marathon and then try out another shoe and do it again. So the lab tests are often very short, five minutes in different shoes, but they are very predictive of performance. But we miss out on some of these long-term effects, like how do these shoes behave at the end of the marathon or how do these shoes help you feel better the next day? So in our lab we study biomechanics and energetics. We don't necessarily build shoes. We work with industry partners like Saucony and Puma where we can request them to make a specific shoe. We have a study coming out actually with Saucony, it was a long time coming, where we went with the first Super Shoe they released. And we then asked like, well, can we get the exact same shoe, but now you make it out of the traditional foam and can we get the exact same shoe, but you leave out the plate. So we were able to do that comparison, but by now, since we're publishing this research, they are up to the third iteration of that model. So science is usually a little slow on that aspect to see what's going on.

ROMA AGRAWAL

I mean, so there has been controversy about these shoes. And my slightly pointed question is, do you see Super Shoes as cheating in a race? Jared, how would you respond to that?

JARED WARD

This is a fair question and a debated question. The term mechanical doping is one that's used in terms of shoes, but much like nutritional products and anti-doping regulations for what athletes are putting in their bodies, this is regulated. And I think I sort of sit in a camp where if you don't like the rules, then you change the rules instead of complaining that the rules are cheating or not set properly. No, I don't consider it cheating. It has changed the game. It's changed athletic performance and is continuing to change it. In periods of great change, innovation, where we're seeing significant effects to performance through the products that are being created and released … that time is a heated time. So when we look back, rewind the clock to 2018, 2019, 2020, when one or two brands have viable performance shoes and other brands are trying to keep up and athletes from a professional standpoint are trying to make careers out of this. It becomes very much about what's on your feet and what are you wearing and how good are those shoes. Now 10 years into this era of Super Shoe innovation, companies have found their niche. They're innovating in different ways. They're using different foams, you know, Wouter talked about the different ways that foams are being created and cut and used, and it levels the playing field a little bit from a professional stance.

WOUTER HOOGKAMER

I think Jared's opinion is really valuable here. So he had his great performance in 2016. And at that point, basically there were three finishers in that marathon that were wearing the first Super Shoe and they were all on the podium. But if even Jared didn't feel like he was cheated out there, then I think who are other people to have an opinion about this? I also think about this question a lot. And I think at that point, it was a big difference between a traditional shoe and a Super Shoe and only a few athletes had access to them. But like Jared was saying, since then other brands have caught up and the differences are a lot smaller now and we're getting faster over time, which is a great thing. So I don't think that's a problem. But then again, with the next innovation that is all of a sudden really big again, it's important to keep that in mind that access is important.

JARED WARD

I think a couple of things here. One is … the issues make things faster. And so that's exciting and it's fun. You can be in the traditional purist camp and not like that change happened quickly, but it is fun to be able to put on a pair of shoes that's going to facilitate you running faster than you've ever run before. That's a fun opportunity. And two, to this less quantified, scientifically, aspect of these shoes, but this idea that I'm not as beat up after a hard training session or after a race than I was previously, I think bought me years as a professional runner. I was running in Sauconys in 2016 in the Olympics and I couldn't walk for days after the race. I came home from Rio with stress fractures in my pelvis and had to take some time off and get back to running. And these shoes, this new cushioned approach to running, I think my body wasn't going to handle running professionally as long in the older traditional shoes than in this. So I'm grateful for that.

ROMA AGRAWAL

I think the word access is the thing that's really stood out for me, you know, making sure that folks that don't have as much money or the sponsorship deals, do they have access to make sure that their bodies can last a bit longer? And this brings me to another point, which is sustainability, obviously a very, very important topic at the moment. And Wouter, I'd love to talk a little bit about how we can have a sustainable approach to the materials that we're using. So the life cycle of the product, while also balancing what performance you're trying to get out of them.

WOUTER HOOGKAMER

The downside of some of these foams is if you foam them up and make them as light as possible, when you run on them, some of these air bubbles in the foam are going to collapse. The foam is going to degrade. So some of these foams are really bouncy, but they degrade pretty quickly. And one of the examples is the recent shoe that is very expensive, very lightweight, but it's only supposed to last maybe a marathon or two, or maybe even one. Because the second one, it would already be worse than your first one. And we have seen that in the past too, where when they were making the shoes as light as possible, they were like, we just need to run one race. So we don't care if the shoe is done after this one race. So we make it the lightest possible. It doesn't have to be able to go 400 miles or 600 miles. Those are sort of the extremes. What we do see overall, these Super Shoes seem to just degrade in foam a little quicker than the traditional foam. So that's a problem. We would have to buy more shoes more often. On the bright side though, a lot of these companies, they have these initiatives where they're going either full cycle and you can return your shoes, or they try to come up with more sustainable materials to make the shoes. Personally, I feel like a lot of that might just be sort of window dressing in a small way where like, well, as a company, we have a million running shoes that we sell a year and 10,000 out of those are sustainable. That's yeah, that's a start, but it's not something to be super proud of yet. There is definitely a lot of room for growth there. And I do see that most companies are aware of that and they're starting pilot projects with like maybe 10,000 shoes that are being able to be fully recycled. There's a lot of talk about, like, if the midsole foam is the stuff that degrades most, maybe we can make a way that you ship back your shoe and we just put another midsole in and we keep the upper and we keep the out. So things like that. So there is definitely innovation happening in this space, but unfortunately on the performance side, yeah, that might be competing. The foams that are better and faster and shoes that are faster are probably not the ones that are most sustainable.

ROMA AGRAWAL

Could you tell us a bit about how far you think we can go with this technology? What's the future of the running Super Shoe?

WOUTER HOOGKAMER

Like nobody would have predicted this. Like we were just making shoes lighter and lighter for as long as we could. And then this whole revolution came in … different focus, different effects, right? And so here now we focus a lot about what can we achieve in this space? And at some point we have diminishing returns, right? Like we can't just run a marathon at no energy cost in two minutes. So there's limitations to how quickly the human body can move, how much forces muscles can produce. You're still running. It's only shoes. You're not on a bike. You're not on roller skates. So within that sort of space, there is room for improvement, but it's also limited. At some point, you just can't move your legs fast enough and you can't produce the forces to not collapse while you're on the ground. The forces that we produce when we are on the ground are enough to counteract gravity, right? But the main part is just fighting with gravity all the time. So shoes can help a little bit with that, but not super much. I mean, I never predicted that 4% shoes savings would be a thing. And we have even seen more than that with the recent versions. So I'm sort of hesitant to think that we can take this very much further than that. At some point, are we even still running? Like we have to expand this energy to move forward. So shoe is only a small part. So I think the biggest thing about the shoes is if we fully get rid of all the energy losses when you hit the ground by making fully hundred percent energy return shoes. And we make that roll off while you're on the ground as smooth and easy as possible, maybe even following a wheel, but not rolling. Some sort of curvature. Even with that sort of scenario, I don't think we will be saving more than a couple of minutes on a marathon.

ROMA AGRAWAL

Jared, how have your speeds changed, do you think, since the Olympics? I'm conscious also that you're getting older, you know, time doesn't stop for any of us. Do you think you're going to get your best times now?

JARED WARD

Age certainly has caught up with me. I just turned 36. I think for me, I'm a little past my physical prime, but not so much that increasing shoe technology could not offset that. You know, if I can stay healthy … and health is a concern, I have more hamstring injuries now than I used to, I'm battling an IT band that just flared up just a couple of days ago. So you know, being a little bit older, the injuries hit more often and they take a little bit longer to heal. And so if Wouter can come up with a shoe that's going to make it so I don't get injured, I would take that over a shoe that's going to save me 2% energy cost. I do think that to Wouter’s comments of where do we go in terms of shoes that are already returning 90 plus percent energy? Well, when we talk about performance, we're talking about energy cost. As we come up with better ways of assessing not only energy costs, but also muscle tissue damage that we may find that the research points us in directions that can optimise performance in other ways. To Wouter’s point, we're not running a marathon in the lab, right? We're running for a few minutes in the lab and we're saying, your energy cost is lower in these shoes, it's 4% better, or it's 8% better and we go run a marathon and our marathon is like 2% better or 1% better, right? Energy cost is not a direct translation to marathon performance. And I think one of maybe the bigger aspects affecting marathon performance is this idea that I can run a marathon now in these shoes and I can wake up and go for a run the next day. I couldn't do that 10 years ago. And so I think as we come up with ways of better assessing how these shoes and how these foams are affecting the muscular damage, the tissue damage that we're experiencing in marathons, we may find that, hey, we've been optimising these shoes for energy cost … Maybe we have reached diminishing returns for energy costs and maybe that's convenient because we're already at 90 whatever percent and we're sort of maxing that out … Maybe this research will guide us and point us towards some things that are going to further impact our muscle tissue damage, and maybe focusing on that is going to lead us another couple percentage points. Because I do think that that's a surrogate that we're trying to measure for when we look at energy cost and we're realising some of that but not measuring it directly.

ROMA AGRAWAL

I have to say I've known that science and engineering play a big role in the design of sportswear, but today's conversation has really highlighted that. And one of the thoughts I'm left with is access. It's, you know, who can access these amazing technologies that improve the health and performance of athletes? So it's not a new question, but it's definitely a very current one. And on that note, I'm going to go off and do my little Couch to 5k week 3 run. No 40 mile or 26 mile runs for me. You've been listening to Create the Future, a podcast from the Queen Elizabeth Prize for Engineering and Peanut & Crumb. This episode was presented by me Roma Agrawal, and produced by Tess Davidson. To find out more, follow QEPrize on Twitter, Instagram, and Facebook. Thanks for listening and see you next time.