By Robert Johnson
January 30, 2019
Tomorrow, World Athletics — the governing body for the sport of track and field — is expected to issue a ruling about what type of shoes will be allowed to be worn in races moving forward. The ruling is heavily anticipated, specifically as it regards the technology used in Nike’s Vaporfly shoes, including the Next% and the (unreleased) Alphafly. The Vaporflys have been the source of growing controversy since they were officially released in 2017, and that controversy reached a fevered pitch in October 2019, when Kenyans Eliud Kipchoge (in the Alphaflys) and Brigid Kosgei (in the Next%) broke the two-hour barrier and women’s marathon world record on back to back days.
World Athletics’ ruling is crucial because it will dictate what technology is allowed at this summer’s Olympics in Japan. And I don’t want what happened at the 2016 Olympic marathon to happen again in 2020. In 2016, three men — Eliud Kipchoge, Feyisa Lelisa, and Galen Rupp — were secretly given Vaporfly prototypes, which were conveniently made to look almost identical to other Nike marathon shoes, and they ended up sweeping all three Olympic medals.
Don’t believe me? Here is a closeup of the shoes worn by the three men’s medallists in Rio.
And here are the three shoes worn by the women’s medallists in Rio — none of which were Vaporflys.
Why is it a big deal? Because there is no doubt that the technology behind the Vaporflys works.
【2019 World Marathon Majors Top 3 shoes】
— Rolows ロローズ (@Rolows_13) November 6, 2019
Twelve of the 14 World Marathon Major champions in 2019 (85.7%) wore a version of the Vaporflys. Of the 42 top-3 finishers across the seven races, 36 were wearing Vaporflys (also 85.7%). If that data hasn’t convinced you, consider the several well-regarded scientific papers that have shown that the shoes boost a runner’s economy compared to other top marathon shoes.
The first study, which was actually funded by Nike, came out in November 2017 and included Olympian Shalaya Kipp on the research team. It said running economy gains in the Vaporflys varied by type of runner, with rearfoot strikers gaining more than mid/forefoot strikers, but estimated the gain to be, on average, about 4% (4.6-4.8% for rearfoot strikers, 3.5-3.7% for mid/forefoot strikers). A paper published in June 2019 by BYU researchers that included Olympian Jared Ward estimated the shoes to be a little less effective, improving economy by 2.8 percent on average. And those papers were only looking at the first versions of the shoe (the first study looked at the prototypes used in Rio 2016; the second looked at the Vaporfly 4%, the first version to be released to the general public). The Next% and Alphafly are both said to provide even greater boosts in running economy.
It’s important to understand that a 3% gain in running economy doesn’t mean that a runner’s time will improve by 3%. So how much faster would an elite pro run with a 3% gain in economy? Well, thankfully there has been a recent scientific study on that matter. A research paper published in February 2019, which also included Shalaya Kipp on the team, says that a pro marathoner’s “predicted percent improvement in velocity is approximately 2/3rds of the percent improvement in running economy.” By their calculations, a 3% improvement in running economy translates to a 1.97% improvement in velocity for an elite pro marathoner. So someone like Kipchoge, who had a 2:04:00 marathon personal best before these shoes were invented, would be predicted to run 2:01:36 with a 3% running economy gain. Kipchoge’s official marathon world record (in the shoes) is 2:01:39.
The shoes work because, with their huge stack height, they effectively extend the length of the leg, and, with their foam and carbon plate(s), help a runner store and return energy. Some supporters point out the shoes don’t return more energy than is put in, but that’s not the point. As 1968 Boston Marathon champ Amby Burfoot wrote, the shoe “increases stride length without requiring additional muscular effort” as the bounce comes in part “from the shoes, not the leg and foot muscles.” Or, as biomechanist and ultramarathoner Geoff Burns told me, the shoes “store and return energy for free — and that comes at a cost when our body does it.”
Put simply: a marathoner wearing the shoes is going to use less energy and be less tired than one who isn’t in them.
“Anybody who understands very basic physiology and mechanics and what goes on with these shoes, there is no question [for them] that they are beneficial,” said Burns. “That’s expert consensus. There’s no question. That’s not a discussion we’re having anymore. The question is whether we are ok with [the advantage].”
Tomorrow, World Athletics will address the shoe technology issue moving forward, but will they also do the right thing and look back? Here is how World Athletics’ rule regarding shoes read at the time of the 2016 Rio Olympics:
Now that it’s established scientific consensus that the shoes improve one’s running economy by several percentage points, how in the world can anyone say that the shoes worn by Kipchoge, Lelisa, and Rupp in the Rio men’s marathon (and by women’s 6th placer Shalane Flanagan and 9th placer Amy Cragg in the women’s race) didn’t provide them with “unfair assistance or advantage”?
Remember, back then, the shoes were a secret. Other athletes had no access to these shoes as they weren’t out yet. Having a secret device that improves your running economy by several percentage points is clearly unfair assistance. In my mind, all of the athletes who wore them in Rio are guilty of mechanical doping.
Remember, track and field is a sport that, in the very same Olympics, stripped Ezekiel Kemboi of his medal for cutting off a fraction of an inch by stepping on the line in the men’s 3,000-meter steeplechase — a race that is nearly two miles long. One inch is .0008% of 3,000 meters. Here, we’re talking about roughly 2% gains in performance.
What would have happened if the shoes weren’t used in the 2016 Olympics? We’ll never know but I do know Kipchoge’s winning time in Rio was 2:08:44 and that Rupp ran 2:10:05 for the bronze. Multiply Kipchoge’s time by 101.97 (to account for the gains in economy), and you get 2:11:16. Multiply Rupp’s time by 101.97 and you get 2:12:39. 4th-placer Ghirmay Ghebreslassie of Eritrea, who was not wearing Vaporflys, ran 2:11:04. Would Kipchoge still have won? Given his track record and considering he just ran with the lead pack for most of the race, it’s quite possible, but would have all of the medallists been the same? I’m not so sure.
Now, I’m not saying the Vaporfly Rio marathoners cheated intentionally. If a sponsor gave me a shoe and told me to try them and I felt great, I’d wear them too. They may have had no idea how much better these shoes were than others. That doesn’t mean they didn’t enjoy an advantage or that there shouldn’t be ramifications.
In an ideal world, the men’s marathon medals from 2016 Rio would simply be vacated. If one thinks that is too harsh of a punishment for what the athletes may argue was inadvertent cheating, then World Athletics should at least make a statement acknowledging that a rules violation took place but without a penalty being given. At least that way there is some sort of an asterisk attached to the results.
This type of thing happens all the time in professional sports. Both the NBA and NFL issue statements after games saying officials failed to call fouls properly. In baseball, the 2017 Houston Astros have been allowed to keep their World Series title but the public at least knows they cheated while earning it. That’s what happened here, even if at the time there was no way for the officials on-site to realize the shoes — which were made to look like other shoes already on the market — were leaps and bounds better than anything else ever invented.
In July, World Athletics told me they couldn’t start an investigation in regards to the legality of a shoe unless they have “conclusive evidence” that a running shoe “gives an athlete unfair assistance or advantage.” Well, we now have that evidence as it’s no longer being debated amongst scientists.
World Athletics is set to act. We know they will be looking forward to the 2020 Olympics and beyond. The question is whether they will also look backward to 2016.
Discuss this article on our messageboard / fan forum: MB: Kipchoge, Rupp, & Flanagan Are All Guilty of Mechanical Doping in 2016 – Will Anything Be Done About It?