Eliud Kipchoge finishing a marathon

Sports tech: Marathon running gear aims to break the two-hour record

Image credit: Getty images

Trying to break the sub-two-hour marathon time is a major challenge, but top sports organisations are all racing to achieve the seemingly impossible target.

In September 2014, Kenyan runner Dennis Kimetto won the Berlin marathon with a time of 2 hours, 2 minutes, 57 seconds, setting a new World Record. His time was 26 seconds faster than his countryman, Wilson Kipsang, who ran the same race the previous year. The marathon world record has been broken 15 times in the last 40 years, athletes knocking 6 minutes 55 seconds off the time set by British runner Ian Thompson at the Commonwealth Games in Christchurch, New Zealand, in 1974.

Now Nike, Adidas and a group of academics from the UK, South Africa, Austria and Greece calling themselves Sub2hours are all attempting to break the two-hour barrier.

Nike is working with three top East African runners – Eliud Kipchoge from Kenya, Lelisa Desisa from Ethiopia, and Zersenay Tadese from Eritrea. Sub2Hours is working with younger athletes, more concerned with research than having an athlete run under two hours in the project’s name.

Racing speeds are determined by forces between a runner’s foot and the ground. Marathon runners want lightweight shoes, but also cushioning to support bones, joints and muscles, and propulsion.

Nike and Adidas have recently released their new sub-two-hour marathon running shoes. Both are keeping their technological secrets close to their chests, but there are a few facts to be found. Adidas’s Adizero is 100g lighter than previous Adidas models, and the Nike Vaporfly Elite weighs around 200g. Adizero has an outer sole made from rubber compound designed with tyre manufacturer Continental that Adidas says lowers the pressure generated when the runner’s foot hits the ground, reducing the chances of slipping. Adidas also says its shoe is made of flexible material with 2,000 particles, enabling it to adapt to individual runners’ feet when on the move.

“The shoe is tight to the runner’s foot, but not too tight, so there’s some room for manoeuvre should the runner’s foot expand when it gets hot during the race,” says Matthias Amm, Adidas’s global running category director.

Angus Wardlaw, Adidas’s director of Future – Running, adds this is important because athletes have different foot stride patterns; some run heel-to-toe, others land mid-foot.

The Nike shoe contains a thin carbon-fibre plate that it calls Zoom X. This, Nike says, helps propel the runner forward and cushions impact forces when the feet strike the road. It also provides enough stiffness to improve the athlete’s ‘running economy’ – a term covering the many physiological and biomechanical factors that contribute to running performance – but not so much that the runner’s calf becomes fatigued through overwork. Stiff muscles and tendons return more energy with each stride a runner takes.

“Two to three times a runner’s body weight hits the surface every time their foot hits the ground, and that energy goes back up through their legs and lower body,” says London Marathon’s former exercise and nutrition adviser, Professor John Brewer. Brewer, now Head of Applied Sport Science at St Mary’s University, adds that if it’s possible, as Adidas and Nike claim, to reuse some of that rebound energy to help a runner’s forward momentum, the runner will become a more economical unit. “The shoes recycle the runner’s energy, but the runner still has to create that energy,” Brewer says.

The Adidas shoe contains something similar, except Adidas calls its foam Boost. “The energy capsules are moulded together to release energy to the athlete,” Amm says.

Wardlaw adds: “The elite athletes we worked with told us they wanted something lighter, more flexible and with better grip. Something that helps them accelerate and decelerate where necessary, turn corners and run on wet areas.”

Wardlaw says Boost can provide a 1 per cent improvement in running economy, but explains that Adidas is looking for further gains by making the shoe even lighter. Wilson Kipsang used the new lighter shoe for the first time in a competitive race at the Tokyo marathon in February. Kipsang won, but his time, although the fastest recorded on a Japanese course, was over a minute off the world record.

According to Nike, to run a sub-two-hour marathon needs a 3-5 per cent improvement. They claim their shoe will have a 4 per cent impact. The International Association of Athletics Federations is investigating next-generation marathon shoes, amid concerns that some may contain illegal springs.

Nike has also designed a running vest, which is apparently based on individual athlete’s body scan data and provides extra ventilation. To go with it, there are skin-tight shorts and Nike aero blade tape on the lower legs to help against drag. This tape contains small nodes (aeroblades) that disturb air moving around the runner’s body, helping it flow past the runner and fold in behind them. The Nike kit also includes arm sleeves to help athletes during cooler temperatures, and socks that provide more ventilation and greater arch support.

However, Brewer is concerned that tight garments covering more skin might also make the athlete hotter, sweat more, lose more fluid and dehydrate. This, he believes, is a bigger problem for marathon runners than being slowed by drag. What Brewer would like to see is a garment with built-in coolant that a runner can activate when they overheat.

The average speed for a 2 hour 3 minute marathon is 2:58 minutes per kilometre. To run under two hours, that would need to come down to 2:50. “The runner who breaks the two-hour milestone would have to pull away 40-50 metres for each mile run, from the existing world record holder, running a current world record time,” Brewer says.

Dr Steve Ingham, the English Institute of Sport’s former head of physiology and now a performance consultant at Supporting Champions, adds that to get someone to run this fast requires a better understanding of the physiological capabilities of the athlete, their lungs, the heart, the blood and metabolism.

“You need to understand all this to enable training, recovery and racing strategies to be tweaked and to run more efficiently during races,” he says. “A small athlete needs a big set of lungs, and contact with the ground has to be at a certain efficiency level.”

This is what Sub2hours researchers are trying to do. They believe the crucial variable is how much force a runner can apply to the ground in relation to their body mass over the course of a race. Also they think there is a lot that influences how well, or not so well, the athlete does this.

A runner’s VO2 max for a start. That’s the maximum volume of oxygen a runner can use. The higher the VO2 max, the more efficiently the runner can deliver oxygen to their muscles while running, and the faster and longer they can run. VO2 max is genetically determined, but can be increased by training.

An athlete’s fluid and carbohydrate intake and a runner’s lactate threshold, past which the runner is no longer producing enough oxygen to enable muscles to respond to activity asked of them, also have a bearing on their performance.

The Sub2hours researchers use a ‘bodycap’ – a thermometer pill to measure a runner’s internal temperature. The pill contains a temperature sensor, a radio frequency antenna, an internal memory drive and a processor that sends temperature data to the receiver unit in real time. The pill takes two hours to reach the gastrointestinal tract and transmits information every 30 seconds if the monitor is nearby. If it’s not, the pill can store information for up to 16 hours. Thermometer pills were originally designed by Nasa and are often used in hospitals and by sports performers who compete in hot weather.

“This technology gives us information as to peak temperatures the athlete reaches during running,” says Professor Andrew Bosch from the University of Cape Town, one of the Sub2Hours experts. “Are there any problems? Is the critical temperature going too high during very fast running? To monitor this you need a constant transmission of temperature data.”

Bosch adds the team are trying to discover how optimum body temperature interrelates with environmental temperature so they can identify the right conditions for the sub-two-hour run. “We ask ourselves – what is the environmental temperature we need to race at so that the athlete’s own temperature doesn’t go up too high?” he says.

The fastest marathon times are always run on flat, straight courses in cold weather. The last six world records have been set in Berlin in September. In 2012, a French National Institute for Sport study found that optimal temperature for the fastest male runners was 3.8°C. Since 2000, over half the world’s top times have been set in October or April.

Nike has selected the Formula One surface at Monza in Italy for the record attempt. The average temperature is expected to be around 12°C, overcast, with very little change in wind direction.

The Sub2 researchers are in less of a hurry. They plan to use satellite data and real-time information about ambient thermal conditions around marathon routes, land surface, air temperatures, humidity, slope and elevation. With information taken from the athlete’s body and environment, over time, they hope to find how an athlete needs to run and where, in order to give them the best chance of running under two hours.

All three are convinced the milestone will eventually be broken. So, too, is Brewer: “I think it’s when, rather than if,” he says. 

Brewer is dubious about it happening in the immediate future, though. Since 1998, the world record has been dropping four times faster than in preceding decades. At this rate, a sub-two-hour marathon would be possible before 2030.

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