ever had trouble believing a "certified" race distance?

daj150

Just a note, friend recently completed a marathon with his Polar watch showing 25.9. I shot him an email so I could relay his story...turns out he was cutting onto sidewalks A TON to get around groups because he got to his race late and was in the last corral. The race was through a city with tons of turns. So there are some cases where a large difference is legit. But typically if your GPS is comes in more than .2 miles under, as @DavidMartinez2 said, the course was short.

The_Enginerd

DavidMartinez2 wrote: »

I ran a marathon a few years ago with a pacer who is also a certifying official. As someone earlier said, because of the way they have to measure tangents and stay close to the curb it is virtually impossible for you as the runner to follow the path they measured. A properly marked and measured marathon should show ~26.4 on your Garmin. If you get 26.2 the course was short.

On my last marathon, I got 26.15. It was a certified course (Boston Qualifier), and I ran all of the tangents. I don't know if the GPS shorted some of the distance where there were out and back sections with turnarounds. I did have it set to record every second, so I wouldn't expect that.

MobyCarp

DavidMartinez2 wrote: »

I ran a marathon a few years ago with a pacer who is also a certifying official. As someone earlier said, because of the way they have to measure tangents and stay close to the curb it is virtually impossible for you as the runner to follow the path they measured. A properly marked and measured marathon should show ~26.4 on your Garmin. If you get 26.2 the course was short.

There is also the issue of GPS error. If you run a straight line, the GPS may spot you at points to the right and left of where you are. Connecting the dots produces a longer distance than you ran. Less commonly, GPS spotting may have you cutting corners that you didn't really cut to produce less distance.

I've been thinking about this since Garmin showed 3.12 miles for my Reindeer Run 5K last Saturday. I typically see about 3.14 miles for a certified 5K when I'm running reasonably good tangents; but Saturday there was snow everywhere. Running good tangents was out of the question. I ran for the least bad footing. So what happened? *shrug* GPS isn't 100% accurate.

taeliesyn

MNLittleFinn wrote: »

Thanksgiving 5k this year was my 3rd race that regisgtered short on my Garmin. Had a 5k 0.04 short, a HM 0.3 short, and this last one 0.05 short. However, 2 other runners who also track on Strava, showed the 5k this year as right on 5k. I may have run a tiny bit less because we were supposed to stay left side of the road, and I did cut some tangents tighter than that.

It also depends on your garmin, I've found my Fenix 2 consistently measures short compared to friends with other garmins. It used to read long, until a few firmware updates ago.

7lenny7

My marathon was on a course with minimal turns (maybe a half dozen) and only 360 runners so bunching up was not a problem after the first few turns. I still logged 26.33 miles on my Garmin.