Running is supposed to be one of the purest sports, but a technological arms race in footwear raises questions about the integrity of competition in athletics.
Times have plummeted in long-distance road races and critics suggest some top trainers are artificially boosting performance.
Such is the concern that World Athletics – the sport’s governing body – has assembled a panel of experts to examine the legality in professional competition of a range of modern footwear.
Eliud Kipchoge wore a Vaporfly prototype – the Alphafly – when he became the first person to run a sub-two hour marathon last year, although the time was not ratified by World Athletics as it was not was not set in a proper race.
Kenya’s Brigid Kosgei also wore Nike’s Vaporfly Next% when she broke Paula Radcliffe’s 16-year-old women’s marathon world record last year.
The shoes, as well as similar models from other brands, feature thick soles and carbon plates that act like springs.
“Universality of Athletics”
While Nike shoes are perfectly legal, an early study published in the journal Sports Medicine in 2017 suggested that Nike’s original Vaporfly 4% offered a boost to running economics – the measure of how much work a runner has to do at a given speed – about 4% compared to another Nike model and a top trainer from Adidas.
World Athletics rules state that footwear “shall not be designed in such a way as to give athletes an unfair assist or advantage”.
Rule 5 adds: “Any type of footwear used must be reasonably accessible to all in the spirit of the universality of athletics.” The Vaporfly Next% are widely available at retail at a cost of over $300.
The wording also indicates that shoes found not to conform “with the rules or the spirit thereof” could be banned from competition.
In a recent statement, World Athletics said a task force, including officials, athletes, scientists and lawyers, was reviewing shoe technology and rule wording.
A decision is likely by the end of this month, but any changes must be approved by the World Athletics Council, according to a spokesperson. CNN has reached out to Nike for comment but has yet to receive a response.
“We have to go with the technology”
Kenyan Kipchoge set the official marathon world record of two hours, one minute, 39 seconds in Berlin in September 2018 and clocked 1:59.40 in the INEOS 1:59 Challenge special stage in Austria. His support runners in Vienna also wore the Vaporfly shoes.
Kipchoge has compared running a sub-two-hour marathon to Neil Armstrong’s historic moon landing in 1969, and the Kenyan sees nothing wrong with the advancement in shoe design.
“They are fair,” he told the Telegraph. “I trained hard. Technology is growing and we can’t deny it — we have to keep up with technology.
Swimming is another sport that has had to deal with the consequences of technological advances.
After 17 world records fell at the European Short Course Championships later that year, the International Swimming Federation (FINA) changed its rules regarding swimwear length and material.
“We’re talking about performance integrity,” respected sports scientist Professor Ross Tucker said, speaking to CNN ahead of Kipchoge’s sub-two-hour attempt in October.
“Is Kipchoge an outlier of immense athletic potential? Or is he just a very good runner who benefits from the immense improvements his shoes bring? Maybe both.
“But the thing is, we don’t know with absolute certainty. Running, especially the marathon, is supposed to be the purest thing humans subject themselves to. It’s just the feet, legs, lungs, heart and brain. These shoes create the same problems that doping poses.