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?

The prospect of seeing one of athletics' biggest stars back on the track is growing stronger, with Jakob Ingebrigtsen reportedly targeting a return to competition later this summer following his recovery from Achilles tendon surgery.

According to comments made by his agent, Daniel Wessfeldt, in an interview with Norwegian media, the double Olympic champion could make his long-awaited comeback at one of three major European meetings in July. The leading options under consideration are the Monaco Diamond League on July 10, the Hungarian Athletics Grand Prix on July 14, and the London Diamond League on July 18.

For athletics fans, the possibility of Ingebrigtsen lining up in London would add another layer of excitement to an already highly anticipated Diamond League meeting. The Norwegian middle-distance sensation has become one of the sport's most dominant figures in recent years, collecting Olympic, world and European titles while consistently rewriting record books.

His 2026 campaign was put on hold after he underwent surgery on his Achilles tendon earlier this year, forcing him to focus on rehabilitation rather than competition. Since then, questions have surrounded when the 24-year-old would be ready to return to racing.

The latest update suggests that decision will largely depend on how his training progresses over the coming weeks. If recovery continues according to plan, July could mark the beginning of his return to elite competition ahead of the latter stages of the season.

A comeback at either Monaco, Budapest or London would immediately place Ingebrigtsen back among the sport's biggest storylines. Each meeting is renowned for producing world-class performances, and any appearance by the Norwegian would attract significant attention from fans eager to see how quickly he can regain top form after his injury setback.

While no final decision has been confirmed, the signs are increasingly positive. After months away from competition, Jakob Ingebrigtsen appears to be edging closer to a return, with London's Diamond League meeting emerging as one of the most intriguing possibilities on his road back to the track.

Should his recovery continue smoothly, athletics could soon welcome back one of its brightest and most influential stars.

What should have been the defining moment of Emad Bashir-Mohammed's young running career instead turned into one of the most talked-about controversies in American road racing this year.

The 23-year-old crossed the finish line first in the men's citizen's race at the prestigious Bolder Boulder 10K on Memorial Day in Colorado, stopping the clock at an impressive 29:50. His performance was not only a commanding victory but also one of the fastest winning times ever recorded in the event's long and celebrated history. Bashir-Mohammed finished eight seconds clear of his nearest challenger and appeared to have secured a breakthrough triumph.

For nearly two hours, he was the undisputed winner.

Then everything changed.

Race officials announced that Bashir-Mohammed had been disqualified after determining that he had started in the wrong wave. According to Bolder Boulder regulations, he had been assigned to the AA wave but lined up with the faster A wave, which began earlier. Event rules allow runners to move backward into a slower wave, but prohibit athletes from advancing into a faster one.

As a result, Bashir-Mohammed's victory was erased from the record books.

The citizen's title was subsequently awarded to Nickolas Scudder, who crossed the line second in 29:58. The promotion handed Scudder back-to-back citizen's race victories, while Bashir-Mohammed was left to grapple with the disappointment of losing a win he believed he had earned on the road.

The disqualification has since ignited widespread debate across the running community.

Bashir-Mohammed maintains that he did not intentionally violate the rules. He claims that after collecting his AA bib, he spoke with race personnel and was permitted to start with the A wave after presenting evidence of his recent performances. In a statement shared after the race, he expressed frustration over the decision, arguing that his goal was simply to compete against the strongest field available and produce the fastest time possible.

Race organizers, however, stood firmly behind their ruling. Officials stated that wave-assignment regulations are clearly communicated in pre-race information and reiterated during packet collection. They also noted that hundreds of participants are disqualified each year for moving into faster start groups, emphasizing that consistent enforcement is necessary to maintain fairness for all competitors.

The incident has divided opinion among runners and fans alike. Some believe the rules must be applied equally regardless of an athlete's finishing position, arguing that wave assignments are a fundamental part of race organization. Others feel the punishment is harsh, particularly if Bashir-Mohammed genuinely received approval to move up before the start.

What remains undisputed is the quality of his performance. On the roads of Boulder, Bashir-Mohammed demonstrated the fitness and speed required to outrun the field by a significant margin. Yet in road racing, crossing the finish line first is only part of the equation. Compliance with race regulations carries equal weight.

For Bashir-Mohammed, the day will be remembered as a painful lesson in the fine margins that can define elite competition. A remarkable run delivered a memorable victory, but a dispute over wave placement ultimately overshadowed the achievement, leaving behind a controversy that continues to fuel discussion throughout the running world.

A fast race, a costly administrative error, and a debate that may linger long after the finish-line tape has been packed away.

The men's 100 metres at the 2026 Rome Diamond League is shaping up to be one of the most anticipated sprint races of the season, with an exceptional field featuring some of the fastest men in the world.

Scheduled for Thursday, June 4, at the iconic Stadio Olimpico in Rome, the race will bring together reigning stars, established champions and emerging talents in a contest that promises fireworks from the moment the gun goes off.

Kenya's Ferdinand Omanyala headlines a world-class lineup that includes American sprint sensation Noah Lyles, Botswana's Olympic champion Letsile Tebogo, Jamaica's explosive Ackeem Blake, South Africa's ever-consistent Akani Simbine and Italy's hometown hero Lamont Marcell Jacobs. With personal bests ranging from 9.77 to 9.97 seconds, the field is packed with athletes capable of producing something special on the Diamond League stage.

Omanyala, the African record holder with a blistering personal best of 9.77 seconds, arrives in Rome eager to continue his strong early-season form and prove he can challenge the very best on the global circuit. The Kenyan star has built a reputation as one of the fastest starters in world sprinting and will be looking to make a statement against an elite field.

Standing in his way is world champion Noah Lyles, whose personal best of 9.79 seconds places him among the fastest athletes in history. The American remains one of the sport's biggest attractions and will be determined to add another Diamond League victory to his impressive résumé.

The race also marks a major test for Olympic champion Letsile Tebogo. The Botswanan star has rapidly become one of athletics' most exciting talents, while Ackeem Blake continues to establish himself as a serious contender on the international sprint scene.

Adding further intrigue is the presence of Italy's Lamont Marcell Jacobs. Competing on home soil, the Tokyo Olympic champion will enjoy passionate local support as he seeks to deliver a memorable performance in front of the Roman crowd.

South Africa's Akani Simbine, Cameroon's Emmanuel Eseme, Great Britain's Jeremiah Azu and rising American talent Jordan Anthony complete a field that boasts remarkable depth and quality.

Men's 100m Entry List – Rome Diamond League 2026

Ferdinand Omanyala (Kenya) – PB: 9.77

Noah Lyles (USA) – PB: 9.79

Lamont Marcell Jacobs (Italy) – PB: 9.80

Akani Simbine (South Africa) – PB: 9.82

Letsile Tebogo (Botswana) – PB: 9.86

Ackeem Blake (Jamaica) – PB: 9.88

Jordan Anthony (USA) – PB: 9.91

Emmanuel Eseme (Cameroon) – PB: 9.96

Jeremiah Azu (Great Britain) – PB: 9.97

With multiple national record holders, global champions and Olympic medal contenders sharing the same start line, the Rome Diamond League men's 100m could deliver one of the fastest races of the year. For sprint fans around the world, all eyes will be on Rome as a stellar cast battles for supremacy over athletics' blue-riband distance.

Audrey Werro announced her arrival as one of the early stars of the 2026 outdoor season with a commanding victory in the women’s 800 metres at the Rabat Diamond League, producing a performance that exceeded even her own expectations.

The Swiss middle-distance talent surged to victory in a brilliant 1:56.56, breaking the meeting record and delivering one of the fastest times recorded worldwide this season. In a race packed with quality, Werro displayed exceptional composure, confidence, and finishing strength to separate herself from the field and stamp her authority on the event.

What made the performance even more remarkable was the athlete's surprise at the level she had already reached so early in the campaign.

"I was not expecting such a strong start to the season," Werro admitted after the race.

The race unfolded at a relentless pace, but Werro remained perfectly positioned throughout. As the athletes approached the bell lap, she glanced at the clock and immediately sensed something special was within reach.

"When I saw the time at the bell, I felt really confident," she said. "I'm really happy with the Meeting Record and looking forward to the rest of the season."

Her confidence proved justified. Maintaining her rhythm over the final 400 metres, Werro powered down the home straight to secure the victory and rewrite the Rabat meeting record books in the process.

The performance sends an early warning to her rivals ahead of a season that promises major championships and high-profile Diamond League battles. Beyond the record-breaking time, Werro's display highlighted her growing maturity as a racer, combining tactical awareness with impressive speed and endurance.

With the outdoor season only beginning, the 1:56.56 clocking suggests that even faster times could be on the horizon. If Rabat is any indication, Audrey Werro may be poised for the biggest season of her career.

Her emphatic victory in Morocco was more than just another Diamond League win—it was a statement of intent from an athlete determined to challenge the world's best throughout 2026.

The city of Boston is set to welcome back one of its most celebrated champions as Kenya’s Sharon Lokedi headlines a world-class field for the 2026 B.A.A. 10K presented by Mass General Brigham Cancer Institute on June 21.

Fresh from another remarkable victory at the Boston Marathon in April, Lokedi returns to the streets of Boston and Cambridge carrying both momentum and confidence as she aims to defend the title she captured in dominant fashion last year.

The two-time Boston Marathon champion has developed a special connection with the historic race city. In 2025, she produced a course-record performance of 2:17:22 to win the Boston Marathon before returning this year to claim another victory in 2:18:51, the second-fastest winning time in the event’s storied history. Her success has cemented her status as one of the premier road runners in the world.

Lokedi will be making her first competitive appearance since her marathon triumph and arrives as the reigning B.A.A. 10K champion after clocking 31:39 over the challenging 6.2-mile course in 2025.

“Boston has become a very special place for me,” Lokedi said ahead of the race. “The atmosphere created by the fans and the community is unlike anywhere else. I’m excited to return and give everything I have to defend my title.”

The women’s race promises to be highly competitive. American Olympian Rachel Smith, who finished second at the Boston 5K in April, leads the domestic challenge. Kenya’s strong contingent includes African 10,000m champion Gladys Kwamboka, former B.A.A. 10K runner-up Stacy Ndiwa, and experienced road racer Viola Cheptoo. British Olympian Jessica Warner-Judd adds further international depth to a field packed with proven performers.

The men’s race is equally impressive, featuring elite athletes from 13 nations.

Ethiopia’s Dawit Seare enters as one of the leading contenders after capturing the 2025 Boston 5K title and bringing the fastest 10K personal best in the field at 27:21. Kenya will be represented by an accomplished group led by Alexander Mutiso, winner of the 2024 London Marathon and runner-up at last year’s New York City Marathon.

Patrick Kiprop also arrives in outstanding form after securing victory at the prestigious BolderBoulder 10K on Memorial Day, while Alex Masai returns looking to continue his strong record in Boston. Masai recently finished ninth at the Boston Marathon and has earned three top-ten finishes at the B.A.A. 10K.

Among the international stars making their mark is South Africa’s Adriaan Wildschutt, who makes his race debut after an impressive season highlighted by victory at the NYC Half Marathon in 59:30. Ethiopia’s Olympic bronze medallist Hagos Gebrhiwet adds further quality to the field, bringing a wealth of championship experience and previous success in Boston.

Canadian national 10K champion Andrew Alexander, two-time U.S. Olympian Hillary Bor, marathon standout Ryan Ford, and reigning USA 25K champion Andrew Colley complete a field stacked with talent and depth.

With defending champions, Olympic finalists, national champions and rising stars all converging on Boston, the 2026 B.A.A. 10K is shaping up to be one of the most competitive editions in recent memory. For Sharon Lokedi, however, the mission is simple: return to the city where she has repeatedly excelled and add another memorable chapter to her growing Boston legacy.