OSAKA -- Japan's Mizuno is considering moving up the launch of its new running shoes to ensure they can be used in this summer's Tokyo Olympics, after new rules prompted by controversial Nike models cleared up questions about what technology is allowed.
World Athletics set new limits on Jan. 31 that stopped short of banning Nike's ultrathick-soled Vaporfly line, which has all but taken over the long-distance running world. The Vaporfly has broken a string of world records, sparking rumors that it could be banned for the Olympics. A prototype version -- barred under the new rules -- helped Kenyan runner Eliud Kipchoge run the first-ever sub-two-hour marathon.
The regulations limit sole thickness to a maximum of 40 mm and allow only one rigid plate in the sole for extra responsiveness and bounce. Significantly for shoe developers, shoes must be on the market by April 30 to be eligible for the Olympics.
The new standards draw the line of eligibility just past the latest Vaporfly, suggesting that World Athletics did not consider it feasible to ban a shoe that has gained such traction among professional and recreational runners alike.
More than 80% of participants in last month's Hakone Ekiden, a widely watched Japanese collegiate relay race, wore Nike shoes. This included the eventual winners, the Aoyama Gakuin University team, long known for preferring Adidas.
"We lost to Nike," said Motoi Oyama, chairman and CEO of Japanese sportswear maker Asics.
The Olympics offers rival sportswear companies like Mizuno a chance to show off competing products.
Mizuno is developing a shoe featuring a sole plate of its own design. The Soka University team wore these during the Hakone Ekiden and broke a record in one section of the race, prompting curiosity about the "mysterious white shoes." The company had planned on a summer launch but is rethinking its schedule.
Asics is also considering rescheduling the release of a new shoe model aimed at competitive runners, featuring a cushioned heel and elevated toes that help to push the foot forward. The launch was originally set for summer at the earliest.
"The design, specifications and materials all follow the current rules," an Asics representative said.
The number of people who use competitive running shoes is limited. But "there are factors that can stoke demand among recreational runners," said Masami Nakanaga, senior analyst at IwaiCosmo Securities in Tokyo.
The competition to build a better top-class shoe "will affect each company's overall sales of running shoes," Nakanaga said.
Sports shoes are Asics' bread and butter, generating more than 80% of its revenue. They account for less than 10% of revenue at Mizuno, which looks to boost its sales. Both hope to capitalize on the attention the field has garnered from the Vaporfly controversy by securing a spot at this summer's Tokyo Olympics, which begin on July 24.
The new rules come less than six months before the games, amid fierce competition for the last few qualifying slots. They are likely to come as a relief for Olympic hopefuls who had fretted over whether they could or should wear shoes that raised questions about fairness and toed the line of acceptability.