Eliud Kipchoge’s historic sub-two-hour marathon will carry an asterisk

By J.S.

THE BARELY thinkable has happened: on October 12th a human being ran 26.2 miles (42.2 km) in less than two hours. For decades researchers have tried to establish a theoretical limit on times for the marathon, often arriving at the conclusion that 1:59:59 was impossible. At the very least, the milestone seemed several generations away from being reached. Yet Eliud Kipchoge, a 34-year-old Kenyan who holds the world record, had a different timeline in mind. On Saturday, as part of the Ineos 1:59 Challenge in Vienna—an unofficial event featuring several artificial conditions—Mr Kipchoge crossed the finish line in 1:59:40. That was almost two minutes faster than the Kenyan’s official world record of 2:01:39, set at last year’s Berlin marathon. It was also 45 seconds quicker than his result at Breaking2, a similar unofficial event organised by Nike in 2017, which produced a time of 2:00:25.

Few of sport’s other barriers have loomed as large. The two-hour marathon ranks with the four-minute mile, bested by Sir Roger Bannister in 1954, and the ten-second 100-metre dash, which was not achieved at low altitude until 1983. The initial response to Mr Kipchoge’s achievement has been euphoric, especially in his native Kenya. The 34-year-old is widely recognized as the greatest marathon runner of all time, with 11 wins in 12 races at the distance, including a gold medal at the Olympics in 2016. When he set his official world record in Berlin last year, the 78 seconds that he shaved off the previous best was the biggest step forward in a half-century.

But inspiring as it was, the master’s most recent performance will not feature in the official record books. Like Nike’s Breaking2 event, the Ineos 1:59 Challenge bent the rules of the IAAF, athletics’ governing body. The location and route were optimised to increase the likelihood of a sub-two-hour time, and a variety of start dates and times were kept open to prevent the weather from throwing a last-minute wrench in the plan. (Similar precautions were taken in Italy for Breaking2, held at the Monza automobile racing track, but a rainstorm left the course well above the ideal humidity at race time.)

The exhibition also aimed to eliminate much of the wind resistance that slows any runner. Mr Kipchoge trailed an electric car, which established a consistent speed for the duration of the attempt, as well as a rotating army of 42 pace-setters in a specially-designed ‘V’ formation. (IAAF rules forbid pace-setters from entering midway through a race, so record-setters are typically forced to run much of their races solo.) According to an estimate by sport scientist Ross Tucker, the benefit of drafting behind the vehicle and other runners was worth two minutes to Mr Kipchoge, itself enough to make up the difference between his official world record and the two-hour barrier. Although perfect conditions are always possible in a regulation race, and it is conceivable that a team of runners as good as Mr Kipchoge could achieve some of the same drafting gains under IAAF rules, most of that two-minute gain would vanish under even the most favourable non-exhibition circumstances.

These shoes were made for torquing

One of the biggest factors in Mr Kipchoge’s 1:59:40 display, however, is fully legal in official races. In Vienna he wore Nike’s latest advance in running-shoe technology: the Vaporfly Next. Its predecessor, the Vaporfly 4%, got its name from the shoemaker’s claim that it improves running efficiency by that margin, a staggering advance that has been corroborated by independent research. The Vaporfly Next has yet to be subjected to the same level of testing, but it is reasonable to assume that it does even more. The 4% model employs a stiff carbon-fibre plate to reduce wasted energy and features a unique design that counteracts some of the ankle injury risk the plate creates. The Next is the first running shoe to use multiple carbon fibre plates among a host of other bells and whistles.

According to Mr Tucker, the 4% advantage conferred by first-generation Vaporflys means that in less advanced footwear, Mr Kipchoge’s 1:59:40 performance would have been good for 2:02:52—an outstanding day at the office, even for an elite marathoner, but far short of the magic number. Not every runner responds to Vaporflys to the same degree, so it is possible they did not help Mr Kipchoge so much. But on the other hand, the Vaporfly Next may have offered an even greater edge than the earlier model.

Vaporflys have been on the feet of elite marathoners since 2016, a short span of time in which the event’s record books have been completely rewritten. Two weeks before the Ineos Challenge Kenesisa Bekele, a 37-year-old from Ethiopia, won the Berlin Marathon with a time only two seconds behind Mr Kipchoge’s official record. And on October 13th, a day after Mr Kipchoge toppled the two-hour mark, Brigid Kosgei, a 25-year-old Kenyan who also wears Nike’s shoes, set a new women’s world record at the Chicago Marathon. Ms Kosgei crushed Paula Radcliffe’s 16-year-old mark of 2:15:25 with a new best of 2:14:04.

Only four men have ever run a regulation marathon in less than 2:02:57, and all of them did so with the assistance of Vaporflys. This group of advantageously shod super-runners have defied the usual pattern, in which new records are established in increasingly tiny increments. The effect of the new technology is unprecedented in distance running, and brings to mind Speedo’s LZR full-body swimming suits, which substantially reduced friction compared to previous standard gear. They were worn by 94% of winners at the 2008 Beijing Olympics, and so many swimming records fell that the suits were quickly banned. IAAF rules for athletics provide little concrete guidance about how to handle this powerful technology, saying only that shoes cannot give athletes “unfair assistance or advantage” and that footwear must be available to all.

Mr Tucker has argued that Vaporflys fail the first test and should be banned, since they are tantamount to putting springs on runners’ legs. Nike is already facing criticism from fans of athletics: on September 30th America’s anti-doping watchdog concluded that Alberto Salazar, a coach who ran the Nike Oregon Project, a programme for elite runners, had encouraged his athletes to take prohibited substances. He has been banned from the sport for four years, though he is appealing the decision and Nike deny any wrongdoing. The company will surely marshal its forces to ensure that their performance-enhancing gear continues to be treated as an acceptable leg up, rather than an artificial boost.

Regardless of whether the IAAF takes an official stance on Nike’s latest creation, the advantage offered by the shoes complicates the task of evaluating the otherworldly feats of the last 13 months. The great barriers in athletics have long captured the public’s imagination in part because so little technology stood between humankind and glory. Bannister managed the four-minute mile in leather shoes on a cinder track. The first men to break the ten-second barrier wore standard-issue spikes.

Such triumphs of the body over the clock are no longer so clear. Fans will rightly admire Mr Kipchoge for his running dominance, but his 1:59:40—and even his official 2:01:39—owe some unknown amount to increasingly clever sneaker design. Thanks to its anti-drafting measures, the result of the Ineos Challenge was always going to come with one asterisk. Given the role of shoe technology, the first 1:59 marathon should probably have two.