In the early hours of Saturday morning, as the sun rose over northern Italy, something remarkable was happening. At least, that’s what $91bn sportswear manufacturer Nike would like you to think.
At 5.45am local time, Eliud Kipchoge, considered by many to be the most talented distance runner of his generation, set out across the tarmac at the Monza Autodrome in pursuit of what he and Nike, his sponsors, hoped would be a world-first: a sub two-hour marathon. We were told by the commentators on Nike’s own livestream of the event that it would be a monumental achievement. The official marathon world record, held by Dennis Kimetto, stood at two hours, two minutes and 57 seconds.
Having kept up with the required pace for much of the way, Kipchoge faded in the closing stages and fell short of his target. However, the Kenyan’s time of 2:00:25 would have knocked a staggering 2 minutes 32 seconds off the world record – if only the event had been recognised by athletics’ international governing body, the IAAF.
Despite the failure to dip under the two-hour barrier, Kipchoge’s feat was heralded by Nike as an inspiration. On Twitter, the company described Kipchoge as running ‘faster than anyone thought was humanly possible,’ adding: ‘The barrier got that much closer.’ While commentating over the company’s livestream – which was the only way to watch the event – Nike-sponsored athlete Shalane Flanagan said: ‘With each step Kipchoge is taking, he is making history.’
But was he really? In the context of sport – as opposed to science or marketing – did any of this matter? Kipchoge was running in conditions that were significantly different from those faced by the men who have steadily driven down the marathon world record since the distance of 26 miles 385 yards was formally contested at the London Olympics in 1908. As well as assistance from Nike’s sport scientists during his preparation, and help with pacing during the race, Kipchoge had a carbohydrate drink delivered to him by a man on a motorised bike so that he didn’t have to break his stride. Lights shining on the ground in front of him showed the shortest way around the course, so that he didn’t have to take a single extra step. And, of course, he was sporting Nike’s most advanced shoes, which purportedly make runners 4% more efficient. Despite some controversy, they are considered legal by the IAAF – and will be available to the public for $250 per pair from next month.
Of course, the idea was to create a situation that was conducive to covering the distance in the shortest possible time. Fair enough. But in addition to these refinements, Kipchoge received a different kind of support.
For all but the last few hundred metres, he was tucked behind a cavalcade of six ‘pacemakers’ running in an arrowhead formation to protect him from the wind. He was also only a few metres behind a Tesla car with an enormous sign affixed to its roof (Watch a recording of the entire run here).
With a rudimentary understanding of aerodynamics and a suspicious disposition my initial thought on seeing the sign, the car, and the arrowhead of pacemakers was that the wind resistance faced by Kipchoge during this run was likely to be significantly less than that encountered by all of those marathon runners who had gone before him. It looked as though Nike had tilted the playing field too much in his favour (Furthermore, Nike’s PR agency has been accused of circulating allegedly doctored images after the event.)
‘I got the same impression as you when I saw it,’ says aerodynamics expert Andy Froncioni, when I call him to get a more informed opinion. Froncioni works for Alphamantis, a consultancy that has been used by Team Sky to help their cyclists go faster. ‘Someone at Nike knew exactly the role of aerodynamics in running.’
Turning to theory for a moment, Froncioni explains that a cylinder of a given diameter will reduce drag for an object travelling behind it. At a distance of 10 times the cylinder’s diameter the reduction in drag is about 5%. At five times the cylinder’s diameter, the reduction in drag is about 25%.
Without knowing the exact dimensions of the car and sign, there is a limit to how precise you can be. But a back-of-the-envelope calculation shows that if the effective ‘diameter’ of the car and sign was in the region of two metres and Kipchoge was running perhaps 10 metres behind it (we know his pacemakers were five metres behind the car), then he would enjoy about 25% of the aerodynamic benefit that he would have had from running directly behind the car and sign. That would be combined (in a quite complicated way) with the additional benefit he received from running behind pacemakers.
This is important. According to a much-cited 1971 study published in the Journal of Physiology, a runner travelling at six metres per second (a shade over the 5.85m/s that Kipchoge was aiming for) expends 8% of their energy overcoming wind resistance on a still day. That’s a big chunk.
Runners in normal marathons alleviate some of this burden by running within the pack, or by staying behind pacemakers for part of the race. But in race conditions – the conditions in which benchmark marathon times and previous records have been set – it isn’t possible for a runner to benefit from lack of wind resistance to the extent that Kipchoge did last weekend.
Interestingly, a source from within the insurance industry tells me that a party sought to insure the bonus payment (reportedly $1 million) promised to Kipchoge if he managed to break the two-hour barrier. However, my source, who has experience of athletic contract bonus coverage, says: ‘The use of a Tesla and advertising board that close to the athletes would add an unknown factor to any potential pricing considerations.’ In other words, without detailed analysis of the effect of the car and sign, there’s no knowing how fast it would be possible for an athlete to run.
Professor Andy Jones, a sports scientist at Exeter University, worked with Nike on the Breaking2 project and was at Monza for the attempt. He acknowledges that Nike set out with the intention of reducing Kipchoge’s exposure to wind resistance with the pacemakers, but claims that the car and sign travelling in front of the runners made ‘absolutely no difference.’ That seems like uncharacteristically strong language for a scientist to use – especially in light of my conversations with Froncioni and the insurer.
When I ask Jones whether it would be possible for me to see the calculations made by Nike’s team that were used to establish this, he becomes tetchy, says I will have to contact Nike directly and soon draws our conversation to a close. But not before claiming that ‘the size and shape of the car [in Breaking2] and the position it is in relation to the runners’ was ‘very similar’ to the setup in ‘most major marathons.’ This, however, is demonstrably untrue.
A quick glance at YouTube footage of the marathon at the Rio Olympics (see below) shows a car in front of the runners but much, much further away.
But why is this important? A runner must work against three forces in order to propel themselves forward: gravity, friction from the ground and wind resistance.
If Nike had reduced the influence of gravity on Kipchoge by, say, finding a course that went slightly downhill for all 26.2 miles, no one would think of this as a true marathon. If the sportswear manufacturer had reduced the influence of friction from the ground on Kipchoge by, say, allowing him to use roller skates or complete the distance on skis, no one would think of this as a true marathon. So, when the company used special measures to minimise the other force holding Kipchoge back – whether it was done using a car, an arrowhead formation of pacemakers, or a combination of the two – surely this ceased to be ‘sport’ as we know it? A valuable science experiment? Yes. A display of athletic prowess? Absolutely. But a ‘marathon’ worthy of the name and all that it implies? No.
‘That’s exactly our philosophy,’ says Professor Yannis Pitsiladis, whom I contact after finding about his an ongoing (and competing) project to help an athlete run the first two-hour marathon in race conditions. ‘I think it’s provided some real data that will be priceless for projects like mine, but what’s happening now is that a lot of public and even the media who don’t understand the difference between a sport and an experiment are referring to Eliud as having run the fastest marathon. No, it’s not a marathon.’
That’s why it wouldn’t really have meant anything if Eliud Kipchoge had managed to break the two-hour barrier on Saturday. Apart, of course, from a bigger boost to sales of Nike’s expensive new shoes.
At the time of publication Nike had not responded to a request to reveal calculations concerning the aerodynamic effect of the car and sign.