Garmin is Not God

The Ten Commandments of Garmin

1. I am Garmin, thou shalt not have any other strange GPS watches, and certainly not that Apple watch.
2. Thou shall not run without being connected to satellites via Garmin.
3. Remember to record all runs. If the run wasn’t recorded, then it didn’t happen.
4. Upload all runs. Strava, or it didn’t happen.
5. Honor thy pace. You are running the pace that Garmin says you’re running.
6. Thou shalt not kill. Remember to keep Garmin fully charged at all times when it is not being actively used.
7. Thou shalt not cheat (at races). Garmin will know and out you.
8. Thou shalt not steal . . . distance. If you ran 4.99 miles, you cannot say you ran 5 miles. Go run the additional .01 distance or whatever distance necessary to get a nice round number.
9. Garmin does not lie. If Garmin measures the race course long or short, then it must be true.
10. Thou shalt not covet another runner’s Garmin. Garmin comes out with new models every year, go out and buy the latest one.

Runners are a funny breed. I’ve been running continuously now for about 5 years, and during this time I noticed some slavish tendencies from runners about their Garmins and their beliefs about the almighty Garmin. I won’t go into each “commandment,” but certainly many runners, including me, have felt the despair of running and realizing the run hadn’t recorded (forgot to press a button, couldn’t connect, the run got erased somehow, etc).

But what annoys me is when runners stubbornly cling onto what their Garmin watches are saying and refuse to believe anything else, as if a Garmin watch could never be wrong (Commandment 9). This is best seen at races when runners claim a certified measured course is long, or even worse, short. Obviously, mistakes can be made (see Milwaukee Marathon and 7 Bridges Marathon & Half Marathon), but in general, a certified course that is properly set out is the correct distance.

A certified course is measured using the Shortest Possible Route (SPR) and includes a Short Course Prevention Factor (SCPF) where 1/10th of 1% of the race distance is ADDED in order to ensure that the race course is the advertised distance. The gold standard for course measurement is the Jones-Oerth counter attached to the front wheel of a bicycle. The course must be measured at least twice and each measurement must come within .08% of the distance, or the course must be remeasured for the third time. (For more details, you can read more here on certified courses.)

A common reason why there’s a discrepancy between the official measured distance and the given distance on Garmin is that many runners fail, especially novice runners, do not run the Shortest Possible Route because they do not run the tangents. But even if you do run the tangents, it’s still quite possible that Garmin will not come up with the EXACT measured distance.

An important detail to notice is how USATF does NOT use a Garmin, or any other GPS device, to measure courses. Garmin relies on satellite to receive information about location and distance. Garmin’s accuracy is within 10 meters, depending upon various conditions, such as satellite signal delays, physical barriers such as tall buildings or large rock outcroppings, internal timing errors, and the position of the satellites themselves. Although Garmins are reliable and accurate enough for normal everyday use, there is enough error that you should not fall prey to the idea that Garmin is infallible. Garmin isn’t God. It’s not perfect.

That accuracy within 10 meters is when the environmental conditions are good. Throw in a few tall buildings (ask any New York runner who has run in midtown) and accuracy goes way off. But even under ideal conditions, when Garmin is calculating your location, it could be thinking that you’re located anywhere within a 10-meter radius of where you’re actually standing. This means that calculations of how fast and how far you’ve been moving is subject to error. You can see this quite clearly when you go to a 400-meter track (most outdoor tracks), and run 12.5 laps on the inside lane. That’s 5000 meters, but I guarantee that your Garmin will think you ran anything but exactly 5000 meters. When I do interval workouts on a track, I use the lap function instead of the autolap feature because otherwise, Garmin overestimates how far I ran.

 

Garmin thought it was moving around all night when in reality it was in the same spot.

One final piece of evidence that I offer is what happened to me a few weeks ago. I was about to go out for a run, so I grabbed my Garmin. Weirdly it was dead (see Commandment 6); I’m anal about having Garmin fully charged. I was in a huff about having to delay the run in order to charge the watch (see Commandment 3). After my run, I obeyed Commandment 4 and that’s when I realized what happened to kill Garmin earlier that day. I had accidentally left Garmin on and it recorded all night long. Because it had been sitting on my sofa all night, if Garmin is 100% accurate, it should have recorded distance traveled as 0.0 miles. Instead, I found that Garmin decided that “I” moved 6.52 miles over 8 hours 9 minutes and 4 seconds. Unless I am to believe that the Holy Spirit took my Garmin (and the Holy Spirit shouldn’t because see Commandment 10) out for a slow run overnight, we can see quite clearly how the errors introduced by Garmin, satellites, and environmental conditions, affect Garmin’s ability to pinpoint its location. As you can see, Garmin was accurate in determining its location, but it’s not perfect. Over the course of the night, Garmin thought it was within 40 feet of its true location, however there a few wild fluctuations, where it thought it moved up to .1 mile away.

 

In short, Garmin isn’t God. It’s not infallible and you shouldn’t live and die by what Garmin is saying. There are no 10 Commandments of Garmin. Runners, chill, and don’t go around telling race directors (or your followers) on how the course was long and you really ran a faster time than the official listed time.*

 

*unless the course really is long because of human error