Track officials have moved to de-escalate the high-tech footwear worn by some elite runners, particularly the specialized Nike prototype that Kenyan star Eliud Kipchoge wore for a historic marathon performance last fall.
World Athletics, the sport’s international federation, announced on Friday that all shoes must meet technical limitations and be available to everyone on the retail market for four months before becoming legal.
The timing is important, with the 2020 Summer Games around six months away.
“It is not our job to regulate the entire sports shoe market, but it is our duty to preserve the integrity of elite competition by ensuring that the shoes worn by athletes elite in competition offer no unfair help or advantage,” said Sebastian Coe, the federation’s president. “I think these new rules strike the right balance in providing certainty for athletes and manufacturers as they prepare for the Tokyo 2020 Olympic Games.”
Shoes can no longer have soles thicker than 40 millimeters and cannot contain more than one rigid plate or blade embedded lengthwise. Spike shoes may have an additional plate, but only to keep the spikes attached.
The Nike Vaporfly, a controversial model available for around $250 on the open market, was not banned.
Kipchoge reportedly wore a prototype called Alphafly, which contained triple carbon plates inside a compressed foam sole designed for improved performance and effort economy.
The reigning Olympic champion and world record holder ran the first sub-two-hour marathon in history in a special stage that did not qualify for a new record as he was the only official participant, surrounded by alternating teams of conductors who protected him from the wind.
A day later, compatriot Brigid Kosgei wore another Vaporfly variant while winning the Chicago Marathon in 2:14:04, setting a women’s world record that is still pending ratification.
Even the most common Vaporfly models have sparked debate since their introduction several years ago. Some people in the track world see them as a natural evolution of footwear, much like high-tech tennis racquets; others think they provide too much help.
Yannis Pitsiladis, professor of sport and exercise science at the University of Brighton in Britain, told Reuters that some shoes amounted to “technological doping”.
In declaring their indefinite moratorium, which takes effect April 30, track officials planned further research, bringing in experts in biomechanics to better understand the technology.
“If new evidence becomes available indicating that we need to tighten these rules,” Coe said, “we reserve the right to do so to protect our sport.”