Do I trust my pace or gps maps?

I have my first half-marathon in two weeks time and I ran my last long run of 2 hours today.  The problem is that I don't know if I should trust my perception of pace or the route mapping programmes online? 

I know that I ran my first mile, which is usually a slower mile at just under 11mins and my last mile (also a slightly slower uphill mile) at just over 11mins.  I was out for a few seconds over 2 hours yet the route maps I have used say that I have done around 10.3 - 10.5miles but I think it should be closer to 11??  I know it is not a huge difference but it makes a big difference to me, psychologically if nothing else.  image

Can anyone comment on how accurate these route maps are and how easy it is to plot an accurate route??

Cheers, Viki


  • Err...they are pretty accurate, especially if you scale them up. What did you use?
  • I used
  • you will have run a bit further as you put straight lines between all the points on the map and i bet you dont run perfectly straight ?
  • Thank you both.  My legs ache today after 10-11miles yestareday so I hope the atmosphere/adrenaline carry me through the extra couple of miles!
  • You should be fine.  I only did a total of three 10 mile runs spread over a year before my first half, due to injuries preventing me from getting more long runs in closer to the event.  I won't tell you that it was easy, but it wasn't actually that hard.
  • If you check the "follow roads" box on mapmyrun it draws your route along the road...but does indeed rob you of all those extra yards you've convinced yourself you've run.

    Good luck TT-where is your race?
  • I had this question in my head the other day. I ran from Yelverton to Tavistock over a country route. I thought it would be at least 10 miles, but it came out of my Garmin as 7 miles.

    I put this down to me running too fast for GPS to keep up, or, alternatively, it could be that my spatial geography is utterly rubbish.
  • 210 - did you check the distance when you uploaded the data to your computer? 3 miles is quite a discrepancy!

  • not too sure...when I upload my to MotionBased, my workouts as per google map and the mbased software seems to state that I run half a mile more than my garmin reads.   And this other software Training Center seems to be 0.1 to 0.2 miles off.

     don't worry and trust your perception

  • Greg C - the short answer is no. The Garmin has been good since I had it.

    The route I cite above was new to me and I merely assumed it's distance rather than using maps to get a gauge.

    I was a tad miffed to have been cheated of three imaginary miles through!
  • Thanks all,

    First race is Brass Monkey's in York.  Just getting myself a little worked up as it has a cut off of 2hr45 but as I did 10.3 - 11 miles in 2 hrs i think I should be good for about 2hr30?

  • I do 10 miles in just under 2 hours and had the same concerns as you when I did my first half, which had a cut off time.

    I made it round in about 2 hr 40 and came last.  But the sweeper said that they would still count me if I went over the cut off time as I had shown the right attitude.  The purpose of the cut off time was to dissuade those who clearly couldn't run that distance and were intending to walk big portions of it, i.e. some fun or charity runners (I know this is a big generalisation on charity runners, but I think you know what I mean).  So don't worry if you are only a few minutes over the cut off, as long as you have done your best.

  • In Chester they run you down and leave you at the side of the road for the council.
  • LOL.  Does that happen in races too?
  • LoL at you two!

    Thanks Caz.  Fingers crossed I will finish in time.  I don't really care about my time I just want to finish.  I am doing a big challenge for charity this year and it is my first race.  A little worried about letting people down.  I think I will be ok once I have finished my first one.  Plus, my second one is Bath so no cut off time there!!!  image

  • SC Ha Ha just got that!!image

  • I'm doing a race with a cut off time soon.  It's 20 miles and I have to finish in under 5 hours.  My training runs show that I will be close to this time so I asked at the club last night (my club are the hosts) how strict they are with the cut off.  They told me that a few minutes won't matter, but that one year they had someone take over 6 hours, and it was beginning to get dark before he finished.  So they brought in the cut off time on H&S grounds.
  • Good luck with that one Caz.  image
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