A note on GPS, Pace, and Marathons

[cowboy]

Since a few of you have purchased the Garmin 305 and are planning to run a marathon within a year, I thought I'd mention an item regarding pace. Allow yourself a little cushion if you are shooting for a specific time.

It seems that you will run more than 26.2 miles in any marathon. Comparing distances with my friends, I have observed total distances that range between 26.4 and 26.9 miles. I think this is due primarily to the crowd. If you are shooting for a faster than average time (sub 4:20,) then you have to pass a lot of people. The bigger the crowd in the race, the more in and out you have to run to get around them.

This means that your actual pace will need to be 8 to 15 seconds faster than the calculated pace necessary to run 26.2 at your goal time. Add this to the 10 second cushion you should have to allow for the slowdown at the wall, and you should train for a pace that is 18 to 25 seconds faster than necessary in order to reach your race time goal.

For those of you who have run marathons with GPS, what did your distance show at the finish line?

[Jeff Lebowski]

In the one I did a couple of weeks ago it showed 26.4.

[Pheidippides]

Since a few of you have purchased the Garmin 305 and are planning to run a marathon within a year, I thought I'd mention an item regarding pace. Allow yourself a little cushion if you are shooting for a specific time.

It seems that you will run more than 26.2 miles in any marathon. Comparing distances with my friends, I have observed total distances that range between 26.4 and 26.9 miles. I think this is due primarily to the crowd. If you are shooting for a faster than average time (sub 4:20,) then you have to pass a lot of people. The bigger the crowd in the race, the more in and out you have to run to get around them.

This means that your actual pace will need to be 8 to 15 seconds faster than the calculated pace necessary to run 26.2 at your goal time. Add this to the 10 second cushion you should have to allow for the slowdown at the wall, and you should train for a pace that is 18 to 25 seconds faster than necessary in order to reach your race time goal.

For those of you who have run marathons with GPS, what did your distance show at the finish line?

I'm trying to account for this by putting down my pace time as slightly faster than what I expect I will actually run (Houston starts in waves based on pace time). The theory behind this is that the people I start with will end up separating from me slightly and I will have to wade through less people.

Having never actually run a marathon, I have no idea if this will work or not. However, my friends who ran Houston last year are the ones who suggested I do it.

4'20" is the average time? Really?

[ERCougar]

My last half finished at 13.0. I was pleasantly surprised. One of my Ragnar legs went an extra 0.2. I was unpleasantly pissed.

I think some may depend on how big you take corners, but some is probably measurement error.

[cowboy]

4'20" is the average time? Really?

Yeah. Here is a good link for stats

http://www.marathonguide.com/feature...apOverview.cfm

If you run a sub 4, you are finishing in the 64th percentile.

[Pheidippides]

Yeah. Here is a good link for stats

http://www.marathonguide.com/feature...apOverview.cfm

If you run a sub 4, you are finishing in the 64th percentile.

I found that. Shockingly, the projected pace calculator on that site has me reaching my goal based on my last run of any noteworthy distance.