I usually run with my Garmin GPS watch and usually at the end of a race, especially the marathon, it shows I ran more than 26.2 miles. Although I know the GPS watch isn’t 100% accurate, it is pretty darn close. However, keep in mind that it’s nearly impossible for a GPS unit to be short. The most common scenario is for a GPS distance to be long. Here’s a sample list of marathons I’ve run and the final distance displayed on my watch.
2011 Kobe Marathon – 26.50 miles
2011 New York City Marathon – 26.42 miles
2011 Houston Marathon – 26.40
2010 Hokkaido Marathon – 26.39 miles
So as you can see, based upon the sample above, I’ve actually run an extra 0.19 to 0.30 miles. This may seem insignificant, but it is adding about 2 minutes to my final time. So how do you minimize the extra distance? When a race course is certified by the RRCA or USATF, it’s measured by the shortest route a person can run and remain on the course, so you need to “run the tangents of the course.” According to the Run to Win web site, what this means is rather than following the curve of a road or your race course, you should aim yourself directly for the next curve that comes into sight and to only run along the curve when you can not see that next curve until after you’ve gone around the current one. Click here for a great article on the subject.
So this is a running tactic I’ll need to practice for my upcoming races and see how it works. Given that I missed a Boston Qualifying time at the recent New York Marathon by 44 seconds, this is something that may help get me there.