Super shoes have ‘blown distance running into a new stratosphere.’ Are they benefitting the sport?

Perhaps the most intense rivalry in distance running currently isn’t between two of the world’s top athletes, although it is being played out at major marathon races across the globe.

When Ethiopian Tigst Assefa crossed the finish line of the Berlin Marathon six weeks ago in an astonishing two hours, 11 minutes, and 53 seconds – eviscerating the previous best time by more than two minutes – the bounds of possibility in women’s running over 26.2 miles were suddenly being adjusted.

It was a ground-breaking victory not only for the Assefa, but also for Adidas – the company responsible for the sleek, platformed shoes on her feet.

“Tigist Assefa … we are so proud of you!” CEO Bjørn Gulden later posted on Instagram.

Fast-forward two weeks, however, and a rival brand was also toasting a world record. Enter Kelvin Kiptum, a 23-year-old Kenyan sporting orange and red-tinted Nikes laced over bright pink socks at the Chicago Marathon.

Kiptum, in just his third ever marathon, finished in a time of two hours and 35 seconds – 34 seconds faster than the old world record held by compatriot Eliud Kipchoge, who is widely considered to be the greatest distance runner of all time.

The two records in quick succession heightened the debate about how carbon-plated shoes – commonly referred to as “super shoes” – are rapidly changing the distance-running landscape. Today, they are worn by virtually all elite marathon runners, both for racing and for training, and by many casual runners, too.

Some are happy about the new technology, arguing that an influx of world records and fast times only serves to advance the sport; others, like long-time coach Peter Thompson, believe that they are an obfuscation, skewing performance and removing a sense of “natural progression” in distance running.

“The brands are not motivated by what’s best for the sport,” Thompson told CNN. “The brands are motivated by what’s best for them, and it then becomes a brand warfare rather than competition between individuals … who’s got the best materials, who’s got the best architecture.

“At the moment,” he added, “it’s become shoe wars.”

Speed over durability

Thompson, who has previously helped the likes of Nike, Reebok, and Hoka to design running shoes and track spikes, refers to the stiff, curved plates in modern running footwear as “external recoil devices” which provide “even greater propulsion.”

Those plates are embedded within thick, lightweight foam soles of no more than 40 millimeters in height, according to guidelines set by governing body World Athletics, and sit below very thin, minimalist uppers.

Take Adidas’ Adizero Adios Pro Evo 1, which hadn’t been worn in a race prior to Assefa’s world record and went on general sale for $500 around the same time. They weigh just 138 grams, have a 39-millimeter-thick heel, and provide the wearer with “greater energy return” by improving running economy, Adidas claims.

Assefa attributed her world record to “hard work over the past year,” but prior to the race had hailed her shoes as “the lightest racing shoe I have ever worn.”

“Running in them is an incredible experience – like nothing I’ve felt before,” she said.

Adidas told CNN that 521 pairs of the shoe were released to coincide with the Berlin Marathon and “sold out in a matter of minutes.” Another drop is set for November.

Designed only to be worn for a single marathon race plus familiarization time, the exact longevity of the shoes will depend “on the athlete wearing them and the conditions they are worn in,” Adidas said.

Their relatively short shelf life has courted controversy: environmental group The Green Runners said that the shoe fosters “an acceptance that increased shoe consumption is fine,” though Adidas rejected the notion that it is a single-use product.

“What we can say about these shoes is that they are designed for performance rather than durability,” Thomas Allen, a sports engineer at Manchester Metropolitan University in the UK, told CNN.

“Whenever you design anything, you’re making compromises in different areas. And I guess in this particular example, it’s like a Formula One car – they’re optimizing to go as fast as possible. They’re not necessarily optimizing for durability.”

Nike, meanwhile, has been a pacesetter in the running shoes arms race ever since its Zoom Vaporfly model was worn by three athletes, including Kipchoge, in the men’s marathon at the 2016 Rio Olympics.

The company’s latest offering – the Alphafly 3, worn by Kiptum and women’s champion Sifan Hassan in Chicago – has been called “the fastest marathon shoe in the world” by Nike. Shortly after Kiptum’s record, it was announced that it would be going on general sale in January 2024.

Asked to comment on this story, Nike told CNN: “We’ve proven in our labs that Nike racing shoes provide measurable benefits, but it’s the athletes on the roads who validate our work.

“The athlete will always be our focus and we will continue to deliver ground-breaking innovations for elite athletes and everyday runners alike.”