How super shoes — and Sebastian Sawe — redefined the limits of the marathon

Sawe’s winning time of 1 hour, 59 minutes, 30 seconds smashed the previous world record by more than a minute. Kejelcha and third-place Jacob Kiplimo of Uganda both also crossed the finish line in London inside the previous world record. The 14 fastest men’s marathon times and nine fastest women’s marathon times have all come since the dawning of the super shoe era.

"Certainly super shoe technology is the biggest factor in the recent increase in performance," said three-time Olympian Dathan Ritzenheim, but he and others argue that it's not the only one.

In other words, it's the shoes — but it's not just the shoes.

Sebastian Sawe of Kenya holds up the Adidas Adios Pro Evo 3 he wore to set the world record in the marathon. (Photo by Li Ying/Xinhua via Getty Images)

(Xinhua News Agency via Getty Images)

The push for sub-2 hours

The distance of the modern marathon can be traced to an accommodation made for the British royal family more than a century ago.

Organizers of the 1908 London Games started the marathon on the lawn of Windsor Castle and finished in front of the royal box at White City Stadium, creating a race of exactly 26 miles, 385 yards after the length had varied at previous Olympics.

A controversial but thrilling finish to that 1908 race helped popularize the marathon and ensure that quirky distance stuck. By 1921, the International Amateur Athletic Federation adopted it as the official length of a marathon.

Had the marathon stayed 24.85 miles like it was at the first modern Olympics in 1896, some runner long ago would have busted through the two-hour barrier. A sub-two-hour time instead became a sort of quixotic quest for marathoners, the barrier-breaking equivalent of the four-minute mile that eluded generations of middle-distance runners until Roger Bannister proved it was possible.

Half a century ago, the men’s world record in the marathon was 2:09.12. A quarter century ago, the fastest time ever produced was 2:05.42. Even when 2016 Olympian Jared Ward entered his first marathon in 2013, one of the most common questions he’d receive was still whether a sub-two-hour marathon was possible.

“I think most of us probably thought, well, yes, eventually,” Ward told Yahoo Sports. “But even for those of us that thought yes, the debate was whether or not we would see it in our lifetimes.”

The desire to ensure that a Nike athlete broke the elusive two-hour barrier led the shoe-apparel giant to assemble a team of scientists, engineers and designers to create a groundbreaking new product. Instead of focusing primarily on making racing shoes lighter as had been the traditional approach, Nike’s innovation team sought to create a model that could reduce energy loss with every stride and improve running efficiency over long distances.

Shortly before the 2016 Rio Games, Nike quietly distributed early prototypes to a select group of elite runners for testing and feedback. The radical new shoes contained a stiff carbon-fiber plate surrounded by thick, lightweight superfoam midsoles, a pairing that combined to store and return more energy than a traditional running shoe could while allowing leg muscles to remain fresher and heal faster.

In 2017, Nike finally unveiled its new super shoe, marketing it as the Nike Zoom Vaporfly 4%. The shoes got their name from lab tests that showed they improved running economy by an average of 4% compared to other popular marathon racing shoes.

Ward recalls feeling incredulous when he first heard Nike’s claims that its new shoes could improve energy efficiency by so much.

“I didn't believe it,” he said. “I didn't believe that shoes could have that drastic of an impact on performance.”

That skepticism gave way to excitement when Saucony sent Ward three super shoe prototypes of its own before the 2017 New York Marathon. Wearing one of the prototypes, Ward ran 4.4% more efficiently than he did wearing traditional racing shoes.

“I will certainly run the race in these shoes this weekend,” Ward said. “And I think you should call them the 4.4%.”

Roger Cheng, Nike's senior director digital innovation, speaking at the launch of the Nike Zoom Vaporfly Elite Flyprint in 2018. (Photo by Patrik Lundin/Getty Images for Nike)

(Patrik Lundin via Getty Images)

It’s not all about the shoes

At the same time as other shoe companies were racing to create prototypes that mimicked or surpassed the Nike Vaporfly, marathon runners also began to benefit from advancements in fueling science.

They’ve found ways to ingest ridiculous amounts of carbohydrates during training and racing as research has suggested that’s one of the keys to avoiding hitting a sudden wall of exhaustion, maintaining running efficiency and reducing muscle damage.

Runners will train their guts to handle as much as 90-120 grams of carbs per hour without falling victim to gastrointestinal distress. They’ll also utilize hydrogels that pass through the stomach to the small intestine, minimizing cramping or nausea and allowing for faster absorption and higher carbohydrate intake.

“Instead of taking in 100-200 calories of sugar an hour, now athletes in heavy training might be taking 500-600 calories an hour,” said Geoff Burns, physiologist for the U.S. Olympic and Paralympic Committee. “When you start stacking very stressful days on top of each other and your body's never getting into that kind of long stress state, you're able to absorb the training so much better.”

The evolution of super shoes and fueling science has altered the way that top marathon runners train for races. Athletes are able to withstand more mileage at speeds approaching race-level intensity without so much risk of muscle strains, stress fractures or joint injuries.

Sawe accumulated more than 125 miles per week while preparing for the London Marathon, his coach, Claudio Berardelli, told the Guardian. At the peak of his training, Berardelli said Sawe ran as much as 150 miles in a seven-day span.

Those numbers are staggering to retired American distance runner Meb Keflezighi, silver medalist at the 2004 Olympics and champion of the 2009 New York City Marathon and 2014 Boston Marathon. In his day, Keflezighi seldom finished a marathon or a long training run without his feet or muscles aching.

“I had the lightest shoes on the market and my feet would be done after 19, 20 miles,” Keflezighi told Yahoo Sports. “I would race on Monday and it would be Friday or Saturday until I could walk again without pain.”

The length of the careers of marathon runners has also increased since Kflezighi’s heyday. Athletes who might previously have specialized in the 5,000 and 10,000 meters are leaving the track behind at a younger age because the race purses and shoe company bonuses are often more lucrative on the marathon circuit. Those same athletes are then extending the prime of their careers into their mid-to-late 30s, aided by the impact of their super shoes and superior fueling.

Then there’s the major marathon courses, many of which seem to be engineered to produce world records. Organizers prioritize smooth asphalt, flat terrain and sweeping turns to ensure that runners can devote every ounce of their energy to forward momentum. They also hire world-class athletes as pacers who ensure a fast, non-tactical race by pulling the lead pack through the first half of a race at a predetermined pace.

There’s one more glaring difference that former American distance runner Dathan Ritzenheim sees between the marathoners that he once competed against and those who he now coaches.

“Mindset,” Ritzenheim says, “is probably the last key component.”

With super shoes on their feet, high-carb gels in their system and hundreds of miles of training building their endurance and mental toughness, today’s marathon runners are more confident going for it early in a race. They have trained their brains to allow their bodies to push the limits of what’s possible.

The morning after Kenyan runner Sabastian Sawe won the London Marathon with a world record time of 1:59.30, the Adidas Adizero Adios Pro Evo 3 running shoes he wore sold out in two minutes. (Photo by Richard Baker / In Pictures via Getty Images)

(Richard Baker via Getty Images)

How much faster can a human run?

One of Geoff Burns’ responsibilities as a USOPC physiologist is to test the capabilities of the newest super shoes that the major brands produce. He then offers feedback to sponsored and unsponsored American distance runners to inform their decisions about which shoes to choose.

For years, Burns described the original Nike vaporfly as “the gold standard” in super shoes, the standard bearer that all the other shoe-apparel giants were chasing, the bar that not even Nike’s subsequent models could beat. Only recently, as Puma and Saucony have unveiled innovative new super shoes, has Burns begun to change his stance.

Puma, Burns said, made the Fast-R Nitro Elite 3 lighter while making slight tweaks to the design of the foam and the carbon-fiber plate. Saucony recently developed a new, more durable foam that Burns describes as “unbelievably good” and “having much higher energy returns.”

The lightweight Adidas shoe that Sawe wore during Sunday's London Marathon sold out in two minutes when it went on sale on Monday, but Burns can't say whether it's worth its $500 price tag. He says he was not wowed when testing previous iterations of that model. He wondered whether Adidas might have stored Sawe’s shoes in individual pressurized canisters the way the company did for some runners who were trying to break the 100K world record last year.

“That is something that could move the dial a little bit,” Burns said.

When asked how much more energy efficient super shoes can get, Burns suggested that “the benefit of technology will plateau soon.” He pointed out that Saucony claims that its new foam returns a whopping 95% of the energy back to the runner with every step

“We don’t have perfect springs yet, but that’s pretty freaking close,” Burns said.

Where the advancements are more likely to come is as runners continue to learn how to better take advantage of this technology in their training and on race days. That’s what could lead to more athletes surpassing the two-hour barrier and lowering the world record.

“In pro running, the marathon now favors the athletes with the big engines that can go fast, take in a lot of carbohydrates, and train in extremely high volumes,” Ritzenheim said. “I think we are just seeing a glimpse of how fast people will run in the coming decade. Breaking down barriers always inspires others to follow the footsteps and the next milestone will come down eventually.”