Running News Daily

Fancy new midsole materials like PEBA make you faster, but at the cost of durability

The eternal question of how long your running shoes should last became suddenly topical a few months ago, when Tigst Assefa set a world marathon record in what Adidas billed as essentially a single-use marathon shoe. This development sparked some important discussions about sustainability, accessibility, and fairness. But it also served as a reminder of how little we actually know about the useful life of running shoes, especially in the new era of thick-foamed super shoes.

Fortunately, there’s some interesting new data in a study from researchers in Spain, led by Victor Rodrigo-Carranza of the University of Castilla-La Mancha. In the Scandinavian Journal of Medicine and Science in Sports, they compare shoes made with a modern super foam to a traditional EVA midsole before and after 280 miles, and find that the new midsole does indeed lose its magic more quickly—so much so, in fact, that the super shoe is no better than the regular shoe at that point.

Before digging into the specifics of the new study, it’s worth sketching in some context. The conventional wisdom that I’ve heard throughout my running life is that shoes typically last somewhere between 300 and 500 miles. This is based on some mix of cumulative experience and imperfect data, some of it published and some presumably locked away in shoe-company filing cabinets.

For example, there’s a 1985 study that measured shock absorption at frequent intervals between 0 and 500 miles, using a machine to simulate the impacts of running as well as two volunteers who racked up 500 real-life miles. Here’s an example of how shock absorption changed with mileage for one particular shoe:

The machine version of running obviously didn’t replicate the demands of in-person running very well, but the two human volunteers show similar patterns. Overall, the human testing found that shoes retained about 80 percent of the shock absorption after 150 miles, and 70 percent after 500 miles. You can see that the curve flattens out between about 300 and 500 miles, which is presumably where the conventional wisdom on shoe lifespan comes from. Conversely, you could argue that once you’re past 300 miles, the shock absorption isn’t going to drop much further, so if you’ve made it that far you might as well keep running in them until they (or you) fall apart. More on that below.

You might wonder whether shock absorption, as measured by a hydraulic machine, is really what matters to runners. More recent research has looked at other metrics: this 2020 study, for instance, used force-sensing insoles to measure the peak pressure on different parts of the foot, testing how it changed as a New Balance 738 shoe went from new, to 215 miles, to 430 miles. As the image below shows, the highest pressures are seen in the midfoot and forefoot:

Those pressures stayed virtually unchanged after 430 miles—but the midfoot peak pressure increased from 388 to 450 to 590 kilopascals, a 50 percent jump. It’s not clear exactly why the midfoot pressure increases. It could be that the relative lack of cushioning in the midfoot makes it less durable; it could be that the higher pressures on the rearfoot and forefoot break down the cushioning in those regions and shift load to the midfoot. Either way, it’s clear that the objective load on the foot has changed after 430 miles. And interestingly, the perceived cushioning reported by the volunteers picked up this change: those who reported feeling less cushioned in the midfoot in the worn shoes did indeed tend to have the highest peak midfoot pressures.

So the overall picture in the pre-super-shoe era was fairly muddy, but basically supported the view that shoes progressively lose their cushioning and reach bottom somewhere in that 300 to 500 mile range. Then came Nike’s Vaporfly in 2017, using a carbon fiber plate and a thick layer of cushioning to promise better running economy in exchange for a few hundred bucks—and, in the footnotes, less durability. The unsourced number that I frequently heard floating around after the Vaporfly’s release was that you should trust them for 100 miles or so.

It’s worth pausing here to say a few words about running shoe foams. Carlos Sánchez at RunRepeat has an impressive and exhaustive primer on the huge range of high-performance foams now on the market, which is worth digging into if you’re interested. A highly simplified history is that most running shoes used to use EVA (ethylene-vinyl acetate), then in 2013 Adidas’s Boost made TPU (thermoplastic polyurethane) popular, and then in 2017 Nike’s Vaporfly made PEBA (polyether block amide) the state-of-the-art. One study found that energy return was 66 percent for EVA, 76 percent for TPU, and 87 percent for PEBA.

While there’s been plenty of chatter about carbon-fiber plates, the weight of evidence is increasingly that most of the magic in super shoes comes from the foams. Unfortunately, the very property that makes them so good—their ethereal lightness—also makes them less durable. Of the more than three-dozen modern foams that Sánchez reviews, the main differences arise from the tweaks manufacturers make to trade off performance and longevity (along with price, of course). That makes it hard to issue general guidance about how long super shoes last: it depends on the shoe and the foam.

Still, one data point is better than zero, which brings us back to Rodrigo-Carranza’s study. The shoes he used were special prototypes manufactured for the study by On, almost identical except that one set had an EVA midsole while the other had a PEBA midsole. Both versions had a curved carbon-fiber plate. Twenty-two volunteers performed a running economy test to measure how much energy they burned at a given pace, once in fresh shoes and once in pre-worn shoes. (The researchers themselves ran exactly 280 miles in each pair of shoes to pre-wear them.)

One key finding: energy consumption in the new PEBA shoe was 1.8 percent lower than in the new EVA shoe. That bolsters the case that the foam itself is a big part of the magic, since both shoes had carbon fiber plates. (Not all PEBA foams are created equal, so we don’t know if On’s foam is as good as Nike’s ZoomX.) The other key finding: after 280 miles, there was no significant difference between the two shoes. The EVA shoe didn’t lose anything at all, whereas the PEBA shoe got 2.2 percent worse.

It’s not worth making any grand extrapolations from a single datapoint about when one type of shoe gets better than the other. Who knows what happens after 280 miles? For that matter, who knows what happened after 26 miles? Moreover, there are lots of other factors that might be relevant. One of the interesting claims in Sánchez’s review is that super foams maintain their properties even in frigid winter conditions, while EVA-based foams get much more rigid. In some shoes, firmness more than doubled after Sánchez’s freezer test. Maybe a worn-out super shoe is still a better bet than a newer EVA shoe for those of us who are latitudinally challenged. He also notes that shoe foams take more than 24 hours to recover from a run, and some recover faster than others, so it makes sense to alternate different pairs in order to maximize both comfort and shoe lifetime.

My own approach to shoe durability is, admittedly, not one that’s easy to generalize. I generally have two or three pairs on the go at any given time, and I run in them until they start to feel flat. It’s a noticeable sensation, especially if one of the other pairs in my rotation is relatively new and bouncy. Then, in the spirit of that graph above showing a plateau after about 300 miles, I keep running in them—but I pay more attention to how I feel during and after runs, and to whether the wear on the outer sole is changing the angle of my footstrike. Once I start to feel a few aches and pains, I retire the flat shoe. That approach works pretty well to keep me healthy, but the new data suggests that it’s probably not maximizing my performance. Anyone want to buy a pair of gently used six-year-old OG Vaporflys?

Melissa Jefferson-Wooden delivered a sensational performance in Budapest, storming to victory in the women’s 100m at the inaugural World Athletics Ultimate Championship in a breathtaking 10.62 seconds.

The American produced a superb display of acceleration and composure to claim the World Ultimate Championship title while recording the fastest women’s 100m time in the world this year. Her 10.62 mark underlined her exceptional form and placed her firmly at the top of the global sprinting hierarchy.

Jefferson-Wooden controlled the race through the decisive stages and maintained her form all the way to the finish to secure a statement victory against a field packed with championship pedigree. She crossed the line ahead of Olympic champion Julien Alfred, who clocked 10.74 seconds with a -0.2 m/s wind, while Sha’Carri Richardson took third in 10.76.

Women’s 100m Final

1. Melissa Jefferson-Wooden — 10.62

2. Julien Alfred — 10.74 (-0.2 m/s)

3. Sha’Carri Richardson — 10.76

The victory was especially significant given the quality of the opposition. Jefferson-Wooden held her nerve against Alfred and Richardson, two of the most accomplished sprinters of the current generation, to produce the fastest performance in the world this year when it mattered most.

Alfred once again demonstrated her consistency at the highest level by taking silver, while Richardson completed an all-star podium in a race that brought together three of the biggest names in women’s sprinting.

But beyond the time, the title and the celebration, one of the most touching moments came after the race when Jefferson-Wooden embraced her father, Melvin, in an emotional celebration.

Their moment carried a deeply personal meaning. When Melissa was just 17 years old, she donated her stem cells to help her father undergo a bone marrow transplant after he was diagnosed with myelodysplastic syndrome. Years later, the two shared an unforgettable embrace in Budapest after she had become the World Ultimate Champion.

For Jefferson-Wooden, however, the evening was about far more than a medal. It was the culmination of an extraordinary journey, now highlighted by a world-leading 10.62 seconds on one of the biggest stages in athletics.

With the Ultimate Championship title secured and her father by her side, Jefferson-Wooden leaves Budapest with more than being an ultimate champion. She leaves with momentum, confidence and a powerful statement of intent — turning a high-profile showdown into one of the defining sprint performances of her season.

Audrey Werro has added another major title to her extraordinary season, storming to victory in the women’s 800m at the inaugural World Athletics Ultimate Championships in Budapest.

The Swiss star delivered a commanding performance, taking control from the opening gun and refusing to surrender the lead as she powered through an absorbing battle against two of the biggest names in the event.

Werro stopped the clock at 1:55.88 to become the Ultimate Championships 800m champion, producing another statement performance on one of the sport’s newest and most prestigious stages.

Behind her, Great Britain’s Keely Hodgkinson fought her way to second in 1:56.26, while the Netherlands’ Femke Broeders-Bol completed the podium in 1:56.74.

The result once again brought together the same formidable trio that featured on the podium at the European Championships, but Werro again proved to be the athlete who could rise above the challenge when it mattered most.

Her Budapest triumph is the latest chapter in a season that has already included records, a successful Diamond League Trophy defence and European Championship gold. Now, she can add the Ultimate Championships crown to a growing list of accomplishments.

Werro’s consistency has been particularly impressive in an 800m event packed with elite talent. Rather than simply relying on a fast finish, the Swiss athlete showed her authority by taking the initiative from the beginning and maintaining enough strength and composure to hold off Hodgkinson and Broeders-Bol all the way to the line.

The victory also underlined the remarkable depth of the women’s 800m, with three athletes separated by less than a second at the finish. Hodgkinson’s 1:56.26 and Broeders-Bol’s 1:56.74 showed just how fiercely contested the race was, but Werro’s decision to dictate the pace ultimately gave her the decisive advantage.

For Werro, this was more than another medal. It was another opportunity to demonstrate that her rise is no passing moment. On a stage featuring established champions and elite rivals, she once again produced the performance required to claim the biggest prize.

For Hodgkinson, the silver medal adds another major podium finish, while Broeders-Bol once again demonstrated her ability to compete with the very best over two laps.

But the spotlight in Budapest belonged unmistakably to Werro.

With another championship crown secured, the Swiss star has strengthened her claim as the athlete setting the standard in women’s 800m running. This is Audrey Werro’s era — and the rest of the field is chasing.

Busang Collen Kebinatshipi has delivered another sensational performance, storming to victory in the men’s 400m at the inaugural World Athletics Ultimate Championship in Budapest.

The reigning world champion stopped the clock at an astonishing 43.39 seconds, smashing his own Botswana national record and moving to fifth on the world all-time list.

Kebinatshipi produced a commanding finish to pull away from his rivals and secure the Ultimate Championship title. American star Rai Benjamin finished second in 44.15, while Jereem Richards of Trinidad and Tobago completed the podium in 44.23.

 Men’s 400m

1. Busang Collen Kebinatshipi — 43.39 NR

2. Rai Benjamin — 44.15

3. Jereem Richards — 44.23

The performance is even more remarkable considering that Kebinatshipi had already rewritten the Botswana record just one week ago in Brussels, where he ran 43.40. In Budapest, he lowered that mark by another 0.01 seconds to establish a new national record of 43.39.

That improvement has also propelled the 22-year-old into rare territory. His latest time now ranks him fifth fastest in history over 400m, placing him among an extraordinary group of athletes who have broken the 43.40 barrier.

Kebinatshipi's victory also caps an extraordinary season for the Botswana star. After establishing himself as a global champion, he has continued to demonstrate that he belongs among the very best one-lap runners in the world.

And there is a major reward for his historic night in Budapest: Kebinatshipi walks away as the Ultimate Champion and $150,000 richer.

From another national record to a place among the five fastest 400m runners ever, Kebinatshipi has turned an already remarkable season into something truly special.

Botswana has its latest sprinting superstar — and Kebinatshipi is showing that his ceiling may be even higher than anyone imagined. 

Marileidy Paulino once again proved why she is the undisputed queen of the one-lap event, powering to victory in the women’s 400m at the inaugural World Athletics Ultimate Championship in Budapest.

The Dominican Republic superstar produced a sensational 49.07 seconds to claim gold, pulling decisively away in the final straight and holding off a fiercely competitive field to extend her remarkable unbeaten run.

Paulino delivered her trademark combination of controlled speed and devastating finishing strength. She remained firmly in contention through the opening stages before unleashing her decisive move down the home straight, where she quickly opened a gap on her closest challengers.

Norway’s Henriette Jæger mounted a strong challenge but could not match Paulino’s finishing speed, crossing the line second in an impressive 49.28. Jamaica’s Nickisha Pryce completed the podium after clocking 49.56, ensuring that three of the world’s leading 400m talents occupied the medals.

The result once again underlined Paulino’s extraordinary consistency at the highest level. She entered Budapest as the world leader after running 48.48 in Paris in June, a performance that also set a Diamond League record. She subsequently remained unbeaten throughout her Diamond League campaign, closing the circuit with a meeting-record 48.64 in Brussels.

Budapest has also become a special venue in Paulino’s career. Three years ago, at the same National Athletics Centre, she captured her first individual world title, marking the beginning of another dominant chapter in her career. She later added Olympic gold in Paris in 2024, further establishing herself among the defining 400m athletes of her generation.

The inaugural World Athletics Ultimate Championship has brought together the sport’s biggest stars in a new winner-takes-the-spotlight format, with Olympic and world champions, Diamond League winners and leading performers competing for ultimate honours.

For Paulino, the occasion once again ended with Ultimate Crown on her arms.

With 49.07 seconds, she did more than win another major 400m title. She delivered another statement of authority, powering through the final straight with the confidence and speed that have made her one of the most dominant figures in modern women’s athletics.

Marileidy Paulino remains unbeaten, remains relentless and, once again, remains the queen of the one lap.

Jakob Ingebrigtsen has made a major decision regarding the remainder of his World Athletics Ultimate Championship campaign, confirming that he will withdraw from the men’s 1500m in Budapest despite producing a sensational performance to win the 5,000m title.

The Norwegian superstar stormed to victory in the inaugural Ultimate Championship 5,000m on Friday night, clocking a season-best 12:59.24 and delivering a devastating finishing kick to defeat Olympic 5,000m champion Cole Hocker and American Parker Wolfe.

Ingebrigtsen’s final 100 metres was arguably the defining moment of the race. The Olympic champion produced a remarkable 12.60-second closing 100m, powering away from the field to secure the $150,000 winner’s prize and underline just how far his fitness has progressed since returning from Achilles surgery.

The victory was particularly significant after what has been an extremely difficult period for the 25-year-old. Earlier in the season, Ingebrigtsen faced serious uncertainty over whether he would even be able to compete at the highest level again. His return has gradually gathered momentum, and his performance in Budapest offered perhaps the clearest indication yet that the Norwegian is rediscovering his formidable racing ability.

But rather than risk pushing his recovering body further, Ingebrigtsen has now opted to step away from the 1500m.

The decision means the highly anticipated showdown with British rival Josh Kerr will not take place in Budapest after all. The two stars had been expected to renew one of the biggest rivalries in modern middle-distance running in the 1500m final.

Instead, Ingebrigtsen is looking beyond the immediate opportunity and towards the bigger picture.

“I’m thinking about 2027… Fitness cannot be faked,” the Norwegian said, signalling that protecting his long-term condition has become more important than chasing another major victory only days after his return to peak-level competition.

The decision comes just one week after an emotionally charged Diamond League Final in Brussels, where Ingebrigtsen finished fourth in the 1500m behind Australia’s Cameron Myers, Kenya’s Phanuel Kipkosgei Koech and American Ethan Strand.

After that race, Ingebrigtsen delivered a fiery assessment of his rivals and questioned the tactics surrounding the pacemaking, particularly involving Hocker. He later acknowledged that there had been “a little too much adrenaline and emotion” when microphones were placed in front of him immediately after the race.

Yet his latest decision shows that beneath the emotion and competitive intensity lies a longer-term strategy.

Ingebrigtsen has already demonstrated that he can compete at an elite level again. His 12:59.24 in Budapest was not simply a victory — it was a statement that the Norwegian remains capable of producing a world-class finish even after months of injury rehabilitation.

Now, however, he is choosing not to gamble with that progress.

For a runner who has spent much of the year fighting his way back from injury, another 1500m race could have offered enormous rewards but also carried unnecessary risk. By withdrawing, Ingebrigtsen is effectively prioritising longevity over one more opportunity for immediate glory.

His message is clear: the comeback is underway, but it will not be rushed.

The 5,000m victory has given Ingebrigtsen confidence, momentum and perhaps, most importantly, proof that his body can once again handle elite competition.

Now comes the harder part — knowing when to stop.

With 2027 already firmly in his sights, the Norwegian has chosen recovery over risk. And after everything he has endured, that could ultimately prove to be one of the most important decisions of his comeback.

Jakob Ingebrigtsen is not walking away from the sport. He is protecting his future in it.