The incredible science behind Eliud Kipchoge’s Ineos 1:59 marathon attempt – Wired.co.uk

Eliud Kipchoge is the greatest male marathoner ever. The 34-year-old Kenyan runner has topped the podium in 11 of his 12 races over 26.2 miles, is the Olympic champion, and holds the world record for the distance: 2:01:39. He also ran the marathon distance in 2:00:25 at Nike’s Breaking2 event in Monza, Italy – missing the two hour barrier by a single second per mile.

And now he has gone one step further by becoming the first to run under two hours for a marathon. On October 12, at a special time trial in Vienna, Kipchoge completed the 26.2 mile distance in 1:59:40. In completing a marathon that starts with “one hour,” Kipchoge broke one of distance running’s final big hurdles. He compared the run as going to visiting the Moon and returning back to Earth.

Before Kipchoge’s 2:00:25 in 2017, there were serious questions around whether a human could run under two hours for a marathon distance. Studies suggested it may take until 2032 to beat the record and a male ceiling on performance could be 1:58:05. However, Kipchoge’s performance in Vienna shows that predictions may need revising.

Like in 2017’s Nike-sponsored event, Kipchoge’s 1:59 doesn’t count as an official world record. This is because it wasn’t part of an officially sanctioned race and used pacemakers that rotated in and out of the run. The attempt was organised by chemical company Ineos, which has links to fracking and is owned by the UK’s richest man, Jim Ratcliffe. But environmental politics aside, there was some serious science behind Kipchoge’s run. Here’s how he did it.

A phenomenal pace

Before we get into what helped Kipchoge cross the line in 1:59:40, it’s worth pausing and considering how ridiculously quick this is. To break it down, it’s under a 2:50 min/km pace for 42 kilometres or around 4:34.5 per mile for each of the 26 miles. Each of Kipchoge’s kilometres were between 2:48min/km and 2:52min/km – meaning at no point did he fall behind the target 1:59:59 pace. Those figures might not mean much when they’re viewed on their own but when compared to regular humans, they’re ridiculous.

According to Runners World, the average 5km finish time in the UK (an equivalent distance to a Parkrun) is 33 minutes and 54 seconds. For men it is 29:08 and women 38:12. Completing a marathon in less than two hours required Kipchoge to run 5km in 14:13, eight times in a row.

Equally, the 10,000m (10km) male world record sits at shade over 26:17 and Kipchoge had to repeatedly run 28:26. A 1:59:59 marathon is the equivalent of running 100m sprints in just over 17 seconds – 422 times in a row.

The right food

Carbohydrates are key to sustained performance in endurance sports – and marathon running is no different. In preparing for the attempt, the organisers created a window (October 12 to October 20) when the run could happen. This uncertainty meant Kipchoge’s food preparations couldn’t begin early. “Because they’ve not had a specific day when they’re going to run, they’ve had to delay the nutritional strategies they’re going to implement before they race,” Stephen Mears, a lecturer in sports and exercise nutrition at Loughborough University, said before the attempt.

Before he started at 8.15am on October 12, Kipchoge will have been increasing the amount of carbohydrates in his diet, Mears says. Muscles rely on carbs, stored in the body as glycogen, to produce force and, thus, power running. If the body runs out of carbohydrates it will start burning fat to fuel an athlete – a process that’s not as efficient and fat is often in short supply in the bodies of elite athletes.

It’s not just before the run that Kipchoge will have been taking on extra carbs. He’ll also had them while he was on the move. “Consuming carbohydrates during exercise will maintain performance or, at least, prevent a drop off,” Mears says. The Kenyan runner was predicted to take on 60 to 100 grams of carbohydrates per hour.

The majority of the carbs Kipchoge consumed during the run was through drinks. He uses a powdered drink, called Maurten, that contains 80g of carbs per 500ml serving.

During the run Kipchoge’s team handed him drinks from bikes riding alongside him – they could be seen handing small bottles to the runner at regular intervals. It was a key reason why the attempt didn’t count as a world record.

Mears says that during the Nike sub-two hour marathon Kipchoge experimented with small drinks (around 50ml) every few kilometres to keep a constant supply of fuel going into his body. Smaller servings take longer to get to the muscles, Mears says, but when compared to large drinks they are less likely to cause gastrointestinal issues.

Psychological boost

Until 2017, the fastest marathon run was languishing in the high 2:02s. Since then, Kipchoge has brought down the official world record to 2:01:39 (set during the Berlin marathon in 2018). This was the biggest jump forward in a the male marathon record in 60 years.

In running 1:59:40 Kipchoge took two minutes off his world record. Unlike in Monza, Kipchoge had a crowd supporting him along the entire course. Nike’s effort was closed to the public, with only a few hundred people in attendance. This time around thousands of spectators lined the Vienna course. “I am the happiest man in the world to be the first human to run under two hours and I can tell people that no human is limited,” Kipchoge said after crossing the line. “I expect more people all over the world to run under two hours after today.”

Pacers to block the wind

Attempting to improve top level athletic performance is all about marginal gains. If it’s possible to make a small tweak that increases efficiency or a result by half a per cent then it’s worth putting the time in to get it right. That’s where aerodynamics come into running a sub-two hour marathon.

Elite cyclists have long known that shielding an athlete from the wind can make huge differences to wind resistance they face. Research has shown that riders in the middle of a peloton – a group of cyclists riding close together to reduce aerodynamic drag – can decrease the impact of wind resistance by 50 to 70 per cent.

The influence of wind resistance is reduced in running – due to lower speeds – but it can still make a difference. During Kipchoge’s record he had the support of 35 pacemakers (with another six in reserve). These were some of the world’s top athletes, who can consistently run the 4:34.5 per mile pace that’s required.

A group of seven pacemakers were in front of Kipchoge in a V formation. Kipchoge was placed at the bottom of the formation with two pacemakers running behind him. During the run the pacemakers worked in teams to rotate in and out of the race during each of the 9.6km laps of the course. They changed positions at the finish line on each lap.

In front of the pacemakers were a series of cars. The one directly in front of the runners was a pace car showing projected finish times and carrying a laser system that projects where the pacemakers should run. Crucially, it acted as a large barrier that can reduce drag. Ineos says the electric car had been altered so its cruise control is more accurate than that of regular models.

Correct weather conditions

Vienna was picked for the marathon attempt not just because the city is largely flat – the event is being run through a large park called Prater. It also has weather conditions in October that are conducive to running fast. The route through Prater was a 4.3km straight, which looped around roundabouts at each end, and was repeated 4.4 times to complete the distance.

On the day, the conditions were ideal for running. It was a foggy, dry morning with temperatures and humidity staying low – the run started at 8.15am to capitalise on the conditions. “A temperature of 10 Celsius is regarded as a fair benchmark for perfect marathon running conditions, combined with low humidity,” Ineos explained in a blog post.

“The issue of humidity – the amount of water in the air – was one of the areas identified for improvement after the 2017 Monza attempt when an early morning rain shower gave rise to unexpected levels of humidity.” Rain can slow runners down by marginally increasing the weight of their clothing and reducing road traction.

There are also other environmental factors about Vienna that increased the chances of Kipchoge running a fast time. It’s at a low altitude (165m above sea level) that increases oxygen consumption when compared with high altitudes and it is only one hour behind the time in Kenya, meaning Kipchoge didn’t have to make a major adjustment after arriving in Austria.

Efficiency enhancing shoes

For Kipchoge’s 2017 Breaking2 event, Nike created a new pair of shoes. The Vaporfly 4% trainers claimed to make runners four per cent more efficient in their movement using a combination of a supersoft foam and a carbon plate. It’s since released an update version that it says has seen some runners getting more than five per cent efficiency gains.

Analysis from the New York Times and an independent academic study has suggested the shoe company’s efficiency claims are true. (The five fastest men’s marathon times ever, all set since 2018, have been run by athletes in versions of the shoe).

But Kipchoge had something new on his feet during his world-fastest time. Before the run, prototype images appeared on Instagram showing Kipchoge training in Kenya in a new version of the trainer that has added airbags and more carbon fibre plates.

On the day, Kipchoge ran in the new pair of “custom” trainers. Nike hasn’t revealed details of these officially but sports website Believe In The Run has dug out a patent from the company revealing details about the shoes. The trainers, called alphaFLY, are said to include three carbon fibre plates, and four pods of aim or foam that are designed to make runners more efficient.

Updated October 14, 2019 10:50 BST: This article has been updated after Kipchoge completed the run