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Professional athletes will not be able to wear prototype shoes after April 30, and other regulations impose restrictions on new shoe technology.

On Friday, the track and field governing body, the World Athletics Federation, announced major changes to its footwear rules. The new regulations immediately prohibit any shoes with a sole thickness of more than 40 millimeters (mm) or shoes containing multiple plates.

The World Athletics Federation also announced that starting from April 30 this year, any shoes used for competitions must be available for purchase in the retail market for four months, effectively prohibiting the use of prototype shoes in competitions.

The new ruling means that Nike Alphafly, which is the prototype shoe worn by Eliud Kipchoge in the less than two-hour marathon in Vienna last year, will almost certainly not be allowed to be used in the competition of participating athletes unless its midsole is reduced. This pair of shoes will be released in the next few months and was recently distributed by Nike to several of its sponsored athletes.

Next%, the previous version of the Nike Vaporfly series, will continue to participate in all levels of competition, because the stack height of its heel is about 40 mm, and the stack height of the forefoot is 32 mm, an average of 36 mm. Although Nike has not announced the details of Alphafly's composition, industry experts estimate that its heel height is more than 40 mm, and may even include three boards. (Runner's World has not yet received a pair of confirmations for testing in our laboratory.) At the time of publication, Nike has not yet answered questions about Alphafly's stacking height or the number of boards.

These regulations are likely to have a huge impact on the future of footwear technology. Because the midsole of footwear contains carbon fiber boards and revolutionary new foams, footwear technology has developed rapidly in recent years.

"It is not our job to regulate the entire sports shoe market, but we have a responsibility to maintain the integrity of the elite competition by ensuring that the shoes worn by the elite athletes during the competition do not provide any unfair help or advantage," Sebastian Ke said, Chairman of the World Athletics Federation. "As we enter the Olympic year, we don't think we can rule out shoes that are generally available for a long time, but we can draw a line by banning the use of shoes that are farther than the current market. At the same time, we will investigate further."

The World Athletics Federation also announced that there should be no more than one plate embedded in the sole of the spike, and the thickness should not exceed 30 mm. Further research will be conducted to examine the impact of the new technology, and a new working group will be established to evaluate new shoes entering the market.

Although the regulations do not mention the Nike Vaporfly, it is almost certain that they are a response to the game-changing effects of this shoe in long-distance running. Since 2016 Nike athletes wore the prototype of this shoe, it has caused heated debate.

In the last US Olympic Marathon trials, former Nike athlete Kara Goucher finished fourth, behind Amy Cragg, Desiree Linden and Shalane Flanagan. In this competition, Cragg and Flanagan wore early prototypes of Vaporfly. "I really don't think it's a level playing field," Gucher, who was wearing Skechers for that game, told Forbes recently. "I think what I have worked so hard to get has been stolen. I can handle that I am not good enough to be able to enter our team, but knowing that the propulsion device in the shoe may prevent me from entering is simply devastating."

In recent years, the World Athletics Federation has faced increasing pressure to take action after claiming that Vaporfly violated its footwear rules. all. "

Although Vaporfly went on sale in 2017, it is said that multiple medal winners of the Rio Olympic Marathon wore the prototype of this shoe in August 2016, which seems to violate the usability rules. However, because the definition of this rule is very vague, it has never been strictly enforced.

As a result, the prototype has been at the highest level for a long time-not just for those running for Nike. During the 2018 Boston Marathon victory, Desiree Linden wore an early prototype of Brooks Hyperion Elite. This shoe contains carbon fiber panels and will be released on February 27, two days before the U.S. Olympic marathon trials.

Geoffrey Burns, a biomechanic at the University of Michigan and former Altra-sponsored runner, and his colleague Nicolas Tam last suggested in the British Journal of Sports Medicine that the stacking height of the heel should be limited to 31 mm in the same year-Nike originally listed for Vaporfly Height, but later tests show that it is 5​​-6 mm thick.

He believes that such regulations eliminate the brand's ability to produce shoes with multiple sections. These technologies may distort the record book and effectively see athletes running on the spring.

"The motivation is to write some kind of very simple regulations that are relatively future-oriented," Burns told Runner's World. "A very simple method is to limit the height. In terms of operation, it is very easy to perform. With the height limit, the more restrictions you have on the [midsole] space, the more other things you put there, or can’t produce huge influence.

"If you have a reasonable height limit, you can't advantageously fit in two plates. Only thicker and thicker shoes can provide the benefits of a board."

The World Athletics Federation has long been criticized for failing to take action to prevent rapid technological progress, but last year it commissioned a working group to consider footwear technology. The team includes two former athletes and experts in science, ethics, footwear, biomechanics, and law. It spent several months discussing its options and reported its recommendations to the World Athletics Commission earlier this month.

Yes. Various studies have found that depending on the model, the running economy of this shoe is increased by 4-5%, which may mean that the race time of elite marathon runners is shortened by 1 to 2 minutes. A source who tested the Alphafly prototype in recent months told Runner's World that it was much more efficient than Next%, and a second source called it "incredible", just like "running on a spring."

The Vaporfly series has changed the shoe game through a variety of factors: the carbon fiber board that runs through the length of the midsole; the Pebax foam (called ZoomX by Nike) is extremely light, soft and responsive; the ultra-thick midsole effectively lengthens the runner’s The legs allow the bottom plate to work at the best angle.

"This ultra-light foam changes the dial for the optimal amount of foam placed on the foot," Burns said. "The cost of carrying the body is lower because it is lighter and returns more energy. In addition to recovering and restoring energy better than other shoes, it has the same weight as other shoes, but now your legs are one centimeter longer Half. This gives you a mechanical advantage."

In the past four years, this technology has had a huge impact: in October last year, Eliud Kipchoge (Eliud Kipchoge) wore Alphafly during the 1:59:40 marathon in Vienna, and in the men’s marathon. When he ran 78 seconds in the race, he used the 2018 world record of the previous Vaporfly series model, which was timed at 2:01:39 in Berlin; in the women’s marathon world record held in Chicago last year, Brigid Cosgay (Brigid) Kosgei) led 81 seconds with 2:14:04; Geoffrey Kamworor wore Next% in the world record of 58:01 half marathon in Copenhagen last September.

The list continues, Strava stated in its 2019 review that the average completion time of marathon runners wearing Next% is 8.7% faster than runners wearing sub-fast shoes.

"If people want to run a marathon wearing Vaporflys or any other shoes, it's not our job to stop them."

This pair of shoes is so effective that many elites competing with Nike’s competitors choose to wear Vaporflys and risk the anger of their sponsors. For example, in the recent Mumbai Marathon, Adidas athletes Dreira Hurisa and Aman Beliso participated in the Next% competition. .

Nike's competitors have responded by developing their own carbon fiber board shoes, many of which will go on sale in 2020. However, because Nike has a large number of patented designs, whether they can be compared with Vaporfly is still open to question.

"From what I read about their structure, I can't imagine them being so beneficial," Burns said. "I suspect that other brands of shoes are much better than their old flat shoes, but if I provide fair advice and you will be on the starting line, you will want to join Vaporflys."

Although improving performance through technological advancement is inevitable, for many people, the question is what the future will look like without supervision. Burns is a 2:24 marathon runner. He believes that the sport needs to be clear before it can get away from its roots. The competition is determined by footwear rather than health.

"Innovation without regulation will be very fascinating," he said. "But for the life of the sport, this is untenable. We don't want the discussion around every game to be about shoes." He described the large number of records in recent years as "a big bowl of ice cream."

Yes. High jump and long jump already have rules that limit the height of shoes, because of the advantage of using thicker soles to compete in these events. The maximum heel height allowed for high jump is 19 mm. In these two competitions, the rules stipulate that the maximum thickness of the front of the sole must be 13 mm.

Many other sports have taken similar actions to regulate game-changing technologies. In 2009, the International Swimming Federation banned the LZR Racer swimsuit after it set a series of world records. It is said that the swimsuit can reduce frictional resistance by 24%.

In golf, the size of driver heads in professional competitions is limited to 460 cubic centimeters. Although many recreational players have no problem with using oversized drivers, this stigma means that most people will use clubs that comply with the rules for the game. However, major brands such as this are still making clubs that are not legal in the competition. It is interesting to see if Nike will push Alphafly to the mass market, even though it is in its current state.

At the elite level, the biggest impact of the new rules is that Nike Alphafly may not be allowed to participate in the US Olympic trials or other major events unless it meets the new standards. Bernard Lagat (Bernard Lagat) is one of the athletes who have seen these shoes training in recent weeks. These shoes could have helped Lagat participate in his sixth Olympic Games later this year. Play a major role.

Given that the company has been two steps ahead of its competitors for a long time, many of Nike's competitors will breathe a sigh of relief in the ruling. Given that all brands will now be forced to innovate within strict regulations, this restriction may narrow the gap. Advances in footwear technology are now likely to produce diminishing returns, because the trend in recent years is that thicker and thicker footwear can use plates to achieve maximum efficiency.

The question now is whether the brand will produce shoes that do not comply with the world's track and field regulations. Given that mid-sized marathon runners will not be subject to shoe inspections, this seems possible.

"If people want to run a marathon wearing Vaporflys or any other shoes, it is not our job to stop them," the World Athletics Federation said in a statement this week. "But if you want to get an approved record, then you are classified as an elite and must follow the rules."

If Nike introduces Alphafly to the mass market, runners may face an ethical decision: Will it be as popular as the previous version, or will runners not want the shame of showing their best performance on substandard shoes?