Marathoners tend to be a competitive bunch, whether they are competing against others, themselves, or both, so they are bound to find the latest—and largest ever—study on marathon results intriguing. The study, lead by Danish statistician and runner Jens Jakob Andersen, collected data on 1,815,091 men and women of all ages in 131 marathons over the course of 5 years (from 2008–2014).
Perhaps the result getting the most attention is that women are 18.6% more efficient marathoners than men. Although women’s times on average were still 7% slower than men’s, women clearly ran a smarter race with more even split times between the first half and second half of their race. Men, on the other hand, tended to go out faster, hit ‘the wall’ at some point in the second half, and slow down dramatically.
Also interesting in the results were that, although men hit their speed peak at age 38 and women at age 24, it was the runners between ages 35–45 for both genders who proved to be the best pacers. Chalk it up to maturity perhaps? Marathon participation is clearly growing in all age groups for both genders, but the leader may surprise you—women 50+ are leading with a nearly 90% participation increase!
Our recent interview with Andersen discussed some of the results, as well as the motivations for conducting the study and personal responses from the results from the man responsible for the largest study ever conducted on marathon results.
THE CLYMB: What is your personal interest and/or history with running?
Jens Jakob Andersen: Being 16 years old I enjoyed running. I jumped the fence to the stadium to train my intervals. I rarely participated in races; I loved the process, not the goal. What I enjoyed so much was improving. The results were measurable! The reason I didn’t become a world champion was, as is the case with many other young hopes, an injury. Today I still enjoy running—especially uphill. Running in the mountains is one of the most pleasured moments for me during my week.
THE CLYMB: What made you decide to conduct this study in the first place?
JA: Initially, I was watching some friends of mine at Ironman Copenhagen. They were great athletes, the best I know. Still they struggled hard in the last part of the marathon. I thought to myself ‘why do they suffer so much?’ How could they all be suffering this much and slow down the pace this significantly? Immediately after the race, I did some manual calculations for participants at Copenhagen Marathon and realized there was a pattern. People spend so much time preparing for a marathon, yet they are generally way too optimistic.
THE CLYMB: What was the process of setting this study up (how long did it take, did you need any special permits or permissions, etc.)?
JA: The process was inspiring and full of learnings. The entire process took 6 months full time and involved people working in 4 different countries. So, first I came up with the idea and asked my Filipino assistant to dig deeper into what races were available around the globe. The result got back to me and then straight to Vietnam, where I had a guy collect all the data into Excel sheets. 1.8 million results is quite a lot. Back to me, and straight to Poland, where a Polish statistician worked out the specified analysis. I would have had loved to make it myself, but Excel cannot handle that amount of data, unfortunately (Excel only has 1 million rows max). Then back to me to analyze the results and come up with the conclusion. A long process. I learned so much, and I deeply appreciate all the people that were involved in this process.

THE CLYMB: What was the most surprising result for you in your study?
JA: Honestly, the most surprising thing to me was that elder women’s interest in marathon running had been picking up so fast lately. Over a 5‑year period their participation rate has increased around 90%. That is massive. True, marathons are getting more popular, but the average growth is nowhere near the growth of elder women. I am thankful for that and I love that they have taken the sport to them.
THE CLYMB: Had you participated in the study as a runner, where would you have fit into the statistics?
JA: Ha ha, I would definitely be a classic example of the average runner, slowing down on the second part. If you ask 100 people if they think they are better than average around, 67 will say they are. Funny, but true. I am an enthusiast and we tend to get caught in situations like this. So I would definitely be slowing down even though I know how bad it would be for my performance. I would do many things not to be one of those guys slowing down, but in the end, I am sure I would slow down.
THE CLYMB: There are plenty of nay-sayers out there about marathoning and how hard it is on one’s body. As someone who has run them personally and well as studied them for years, what is your response to marathon nay-sayers?
JA: Actually, I am not necessarily a fan of marathon running. I am a fan of the process of training so hard that you can accomplish a marathon. To me, everything is relative, and I can be just as inspired by the overweight guy who lost 20 kg and then in one day biked 100 km, when he couldn’t have ridden a bike 6 months earlier. We all come from different stages. Regarding marathon running and the health benefits and challenges, there are pros and cons. If I could choose only between a) every single person did marathon running and ran 40 km/week and b) no one ran or did other sports, I would vote for a). That being said, marathon running is very hard on the body and I prefer shorter runs.
THE CLYMB: As an ultra-running enthusiast, I have to ask—are you planning to study ultras next?
JA: Great question! The challenge about ultra running is that typically the event-makers of ultra races are good at planning very varied routes, which will make the data insignificant in many cases. I will have to find another angle to it, but I do definitely think it is interesting.