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The Science Behind the Sub-2 Hour Marathon

Authored by Sumaswara Chinthalapati

Imagine running a four-and-a-half-minute mile. That time itself is phenomenally fast with only an estimated less than 1% of the population being able to achieve it. Now imagine running this same incredible four-and-a-half minute mile for twenty-six miles straight. This pace would guarantee a marathon time finish of under two hours, an achievement that was considered near impossible by many elite athletes and scientists. The late Olympic marathon gold medalist Sammy Wanjiru went so far as to say, “For me it's impossible to run [a marathon under] two hours…in this generation, you cannot talk about two hours.” [1] Just less than a decade after Wanjiru dismissed the idea of a sub-2-hour marathon, Kenyan long-distance runner Eliud Kipchoge broke the limit with his superhuman time of 1:59:40.2. 

This performance, although not officially recognized as a world record, was achieved at the Ineos 1:59 Challenge, an attempt by Kipchoge, scientists, and other athletes to break the two-hour mark for running the marathon distance. To truly understand the impressiveness of this speed, we must recognize the fact that “[Kipchoge] ran at a pace of 13 miles per hour, for two hours in a row” [2]. The real question behind this whole endeavor is how. How did Eliud Kipchoge break the limit that was considered impossible by most, if not all, athletes and scientists? Despite the many factors that played a critical role in this accomplishment, such as a hardcore mindset and extreme training, the answer comes down to one thing: the science of running. Three main scientific factors govern a runner’s speed: rate of oxygen consumption, running efficiency, and endurance capability. [1] And for Eliud Kipchoge to be able to run a 1:59 marathon, all those factors had to come together perfectly. 

The first factor, maximal oxygen consumption, also known as VO2 max, is “the main measurement of a runner’s power” [3]. It is defined by the maximum amount of oxygen that the athlete can utilize during intense exercise. Most elite runners use about 80% of their VO2 max during a race and so far not much can be done about breaking this limit other than “turning to performance enhancing drugs” [3]. However, blood doping and performance-enhancing drugs are illegal in marathon running. So when faced with the factor of ensuring maximal oxygen consumption, the scientists in the Ineos 1:59 Challenge turned to the environment. They chose the race to take place in Vienna, not only because the course was relatively flat but also because it’s at a low altitude of only 165 meters above sea level. This secured maximal oxygen consumption for Eliud Kipchoge as he was running. 

The second factor, running efficiency, determines how quickly a runner can cover ground. Running is inherently full of inefficiency as “only about 45% of the power generated by our legs actually pushes us forward” and the rest is wasted [3]. To improve running efficiency, Kipchoge ran in custom-made unreleased Nike trainers called alphaFLY which “are said to include three carbon fiber plates, and four pods of aim or foam” [4]. These springy shoes allowed a return of energy to the legs during every stride to minimize energy dissipation. In addition to factoring in the energy lost during the runner’s strides, the scientists also accounted for wind resistance which usually slowed down other runners by a considerable margin. Kipchoge ran with a team of 41 pacers. Five were constructed in a V-shape ahead of him to reduce drag and improve aerodynamics, similar to the tactics birds use when flying. Two pacers ran behind him to push him forward.

The final factor, endurance capability, is the most important when it comes to running intense distances at such a fast pace. For Kipchoge to run twenty-six miles at the incredible pace of 13 miles per hour requires tremendous stamina, as the body begins physiologically breaking down after a certain number of miles. The key to sustained performance in marathon running is carbohydrate intake. Carbohydrates stored in the body as glycogen “produce force and, thus, power running” [4]. When the body starts running out of carbohydrates to produce fuel from, it starts relying on fat which is inefficient and “often in short supply in the bodies of elite athletes” [4]. Not only did Kipchoge start increasing his carbohydrate intake before the race, but he also consumed carbs through drinks during the run as well. The Ineos 1:59 Challenge team handed him drinks during regular intervals which allowed him to “take on 60 to 100 grams of carbohydrates per hour” [4].

Although the incredible marathon time of 1:59:40.2 was not recognized as an official world record due to factors such as pacers and interval carbohydrate intake, this feat proved that humans are capable of breaking down barriers previously thought to be impossible. From understanding the science behind peak running performance, scientists and elite runner Eliud Kipchoge were able to break the 2-hour limit and make yet another giant leap forward in what is considered humanly physically possible. 

Works Cited

  1. BBC. (2011, April 11). Could a marathon ever be run in under two hours? BBC News.  

  2. Crouse, L. (2019, October 13). How did Eliud Kipchoge break the marathon record so soon? The New York Times. 

  3. What will it take to break the 2-hour marathon? - science. (n.d.).  

  4. Burgess, M. (2019, October 14). The incredible science behind Eliud Kipchoge’s 1:59 Marathon. WIRED UK.  

  5. Vo2 Max testing. Exercise Physiology Core Laboratory. (2023, April 25).,cardiovascular%20fitness%20and%20aerobic%20endurance

319 views3 comments


Fine presentation about science behind marathon


Remarkable appreciation



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