Measurements…

Course measurement is a critical part of any race and with the proliferation of GPS watches, is something that sparks plenty of post-race discussion. Prior to these watches becoming a relatively common asset, there was no easy way to see how far you ran compared to the published distance. Now, it’s easy for us to stop the watch at the finish line and check, and it’s not uncommon for the GPS to be close but a bit different.

I created a 5K course last spring for a few of us to do for a time trial. In the couple of weeks leading up to it, I ran the course multiple times and always came up with 3.1 miles. When we ran it, the course came up short. This baffled me. It was along a trail that I use frequently and in the days following the time trial, I noticed that my measurements were showing differently: long, short, and spot-on, depending on the day.

Similarly, when I ran the virtual marathon earlier this fall, I had the course picked out based on past measurements. On the day of, my watch and phone were giving me different mileage and neither matched the prior distance marks. When a few of us did a time trial on a track and ran the exact same distance, our watches were all slightly different.

If my watch doesn’t match the published distance, either long or short, then unless a course is way off, I’ll just go with the advertised length but acknowledge the caveat of the measurement. It’s possible my watch was right, it’s possible their measurement was right.

One way to know with certainty that you’re covering the full distance is to run a certified road race course. The one downside here is that these are measured to be at least the race distance. The organizers take the course and measure the shortest possible way someone can cover the 5K or marathon or whatever distance is advertised. This is important because if someone does set a record, they need to have covered the full distance and not be even a little bit shy of it. It also means that unless you’re able to run the shortest possible version of it, you’re going to be a bit long on your final mileage. The easiest way to cover your exact distance is to go to a track. If you stick to the inside line (and don’t step over it) the entire time, you will go the precise number of miles or kilometers you’re aiming for.

I ran a 5K yesterday. The weekend prior to the race, a friend of mine and I had run the course twice to get familiar with it and plot out our race strategy. When I got there and saw where the finish line was set up, I was surprised to see that it was a little short of where we figured it should have been. At the end of the race, my watch showed 3.06, or .04 miles off of the full 3.1.

My time goal had been a 19:55 with mile splits of 6:20/6:40/6:10. I ended up with a 19:25 and 6:23/6:38/6:03 on my watch. It’s possible the course wasn’t quite 3.1. On the other hand, I felt better than expected in the last mile and was pushing hard, so maybe it was a good day. Given that the time difference wouldn’t have pushed me past any major threshold and that the difference was within a reasonable margin of error, I’ll take the time.