Skip to main content

Measuring Marathon Courses by Bicycle

translated by Brett Larner

The full marathon is a sport where you compete over 42.195 km, but how do they go about measuring that distance?  Today we're going to look a little bit at how they go about certifying the distance of a marathon.

The reality is that major international marathons use a bicycle to measure the distance.  This rule is an international standard, and the same method of measurement is used everywhere.  It was put into place in 1986.  In order to ensure that the same method is used everywhere, a bicycle that meets IAAF specifications must be used for measurement.

In the case of Japan's major marathons, to be certain that the distance is correct a provisional measurement is first made.  Before the course is certified using a bicycle the course is measured using a 50 m-long length of wire to determine that it is in fact 42.195 km.  When a bicycle is used the estimate of the distance can vary slightly depending on the weight of the rider, so the Japanese method of using a wire is probably more accurate.

When it comes to course measurement the IAAF has a lot of other rules as well.  Believe it or not, one of them is that the course can be up to 0.1% too long and still be certified as an accurate distance!  That means that the IAAF has decided that a marathon course can be 42 m too long and still be considered OK.  Conversely, they specify that if a course is a little bit short it won't be certified.

To avoid that there are a lot of cases where they add a little extra to the distance.  Even at races where government bodies are acting as the organizers!  You can find reports that the distance of a race was incorrect, and if you research it a little further you will find that in a lot of instances the organizers didn't have enough time to measure the course on foot and that it was done by car instead!  As a consequence many races have fundamental errors in the distance of their courses.


Anonymous said…
The article leaves out a lot that goes into certifying a course and offers inaccurate info also. Using a 50 meter length of wire is NOT necessarily a more accurate way to measure a course - it's tedious, time consuming, bothersome (dealing w/traffic) and, as mentioned, not necessarily more accurate than using a bike. I know these things because I've measured courses for certification in the US (Michigan) since 1981.

To be certified, measurements include a .1% short course prevention factor (SCPF) to calculations. Note I say calculations and not to the course length. Our measurement technique isn't foolproof but has proven to be the most accurate around - thus we add the .1% to calculations to ensure the course is at least long enough.

Scott Hubbard
Anonymous said…
This article explains it very well with pictures etc

Most-Read This Week

Kawauchi Named Captain of Japanese National Team for London World Championships

At a JAAF event at the British Embassy in Tokyo on July 21, marathoner Yuki Kawauchi (30, Saitama Pref. Gov't) was named men's captain of the Japanese national team for next month's London World Championships. Javelin throw national record holder Yuki Ebihara (Suzuki Hamamatsu AC) was chosen as women's captain.

In a wide-ranging and impassioned speech 4 minutes and 20 seconds long, Kawauchi stoked the team's morale as he told attendees, "I think that there are athletes here today who look at London as just a checkpoint along the way to the Tokyo Olympics. But as a representative of Japan it is not enough just to be there competing. I feel it strongly. You must produce results at this event, the London World Championships. This is the task assigned to each and every one of us. It is critical that we work seriously to achieve our goals. The Japanese people want nothing less. What can we as athletes do for them? More than just wearing the uniform, each of us mus…

'$500,000 USD Prized Asian Premier Marathon Series 2017-18 Launched in Beijing'

A very interesting World Marathon Majors-style development with prize money only for Asian athletes. Equally interesting is the absence of a Japanese race in the series. Japanese marathoners would dominate the series if they ran its three component races, their only real current competition in Asia coming from East African-born Bahraini athletes.

Hayakawa and Ichiyama Win Shibetsu Half

2nd in 2015 and 3rd last year, Tsubasa Hayakawa (Toyota) finally succeeded in scoring 1st at the Shibetsu Half Marathon, outrunning 2013-14 winner Masato Imai (Toyota Kyushu) by 6 seconds to win in 1:03:38. Hayakawa pushed it from the early stages of the race, Imai the only one to try to stay with him but ultimately losing touch. 2016 Beppu-Oita Mainichi Marathon winner Melaku Abera (Kurosaki Harima) was 3rd in 1:03:51.

日差しが強くなってきました…💦 — はたのまき (@machakin77) July 23, 2017
The women's field was split between two distances, 10 km and half marathon. Kanako Takemoto (Daihatsu) won the 10 km in 34:27 by a margin of almost 10 seconds over an Otsuka Seiyaku trio led by Ayaka Inoue. 2017 National Cross-Country champion and last year's 10 km runner-up Mao Ichiyama (Wacoal) took the top spot in the half marathon, outrunning teammate and national record holder Kayoko Fukushi and others to win in 1:14:01. Fukushi finished 4th in 1:15:41 behind last ye…