When looking at my professional background (Software Engineer) it seems kind of obvious that I always try to read facts out of data. But there is data that I’m more interested in than other data sets. As a passionate runner I like to have a closer look into race results data, especially on long distance races with a lot of runners like the big marathon events. As the marathon race season in the northern hemisphere comes to an end, I’d like to share some insights found in results data from some bigger events of this fall.
I will start today with some analysis of this years Chicago Marathon. The Chicago Marathon became fourth biggest marathon by finishers world-wide since first held in 1977. Tens of thousands of amateur runners finish this race each year. Also for the pro athletes it’s a race to consider as it is one of the six World Marathon Majors races and an IAAF Gold Label event.
For this analysis I extracted the official result data from the Chicago Marathon website and saved it into a database so it is easy to query the information.
I collected some of my findings into an infographic that you see below.
As far as gender distribution of the runners the trend from recent years continues and the amount of women finishing Chicago Marathon keeps growing. Almost 46% of the runners are women a significant increase compared to the 39% in the year 2000.
More than 90% of the finishers are between 25 and 64 years of age. I expected a bit more young runners than just 7.6%. The average age for male runners is 40, women are quite a bit younger with 36.4 years. The fact that there were again hundreds of runners older than 65 years shows that endurance running is a sport that can be done on a decent level for decades.
Kenya’s runners showed an impressive performance in both the men’s and the women’s races. The first five men were from Kenya and the first four women. However when averaging the finish time for all 25 athletes from Kenya they only end up in third place. Winning the average are the five runners from Ethiopia followed by Slovenia. The first nation from Asia is China in 7th place. Runners from Great Britain are in the middle of the 78 nations running this years Chicago Marathon. Team USA averaged a finish time of 4 hours 40 minutes and ended up on one of the last places probably due to the fact that most amateur runners were from the USA. The small number of runners from small and distant countries suggests that the amount of pro or ambitioned amateurs is quite high for these countries.
With an overall average finish time of 4:34:47 the 2016 edition was the slowest Chicago Marathon since 2011. However almost a third of all runners managed to finish in less than four hours. The fastest age group with a time of 4:30:32 is 35 to 39 years of age and averages the time of 16.1% of overall finishers.
It’s widely accepted that you shouldn’t start out to fast in a marathon to achieve the best results. Actually most runners should try to run the second half of the race a bit faster than the first. In this years Chicago Marathon only 9% of the runners followed that rule.
Another interesting thing to look at is how the amount of runners distributes in the different age groups and what their average finish time is. The following two diagrams show the runners per age group (line) and the average finish time (bars) for each age group for men and women. In general the fastest and the most runners are between 25 and 39 years of age and the numbers decrease with each age group. However there are some noteworthy differences between the men and women data.
The fastest and biggest age group for men runners is 35-39. In the female groups the data shows another picture. In both the 20-24 and the 25-29 age group there are more runners than in the respective male age groups. The latter one being the largest age group among women and also the fastest one. Besides this significant age difference for competitive runners by gender there is also a difference on the upper end of runners age. For women there was not a single runner in the 80+ age group. Also female runners between 75-79 are faster than the runners between 65-74.
If you look at the bars that represent the average finish time for the age groups you see that the pace for older runners decreases more among men runners compared to female runners. The curve for women is relatively flat and not a single age group has an average finish time of more than six hours. The two oldest male groups average more than 6h as the oldest female group is faster than the two younger age groups as noted above.
I also looked at the 5k split data that allows to see the development of running pace over distance. As you probably know it is beneficial to run a steady pace throughout the entire marathon and not to start out to fast so you can speed up towards the end. Most runners however slow down the more miles they covered. The fastest runner (winner of the men competition) was able to get faster in general with a small slowdown between kilometer 25 and 30.
Also the top 100 finishers run a relatively constant race with just a slow decrease in average race pace over time. The rest of the runners however show a significant slowing starting with an average of 6 minutes per kilometer and running the last stretch with almost 7.5 minutes kilometers, so a 25% decrease in pace.
So that’s it for the Chicago Marathon 2016 result data analysis. I’ll do the same for the world largest marathon, the NYC marathon that took place last Sunday, in the beginning of next week.