Official race distance vs actual distance run

Official race distance vs actual distance run

Poppy Field Poppy Field

Hi. Couldn't think where else to put this so here it is!

Ran my very first race yesterday - the Bristol 10km. I'd really hoped to do it in an hour but actually recorded 1.10.37. However, I also used the fitness app on my ipod to measure my pace etc on the way around - and it recorded I'd actually run 11.67km! I swear I didn't hit 'start' until I was over the line and remembered to stop it once I'd crossed the finish line so, even allowing for some inaccuracies, it still seems I ran further than the 'official' distance. Of course, that means everyone else must have done too to some extent :-D I'm guessing this was due to weaving in and out overtaking and - through my own lack of experience - not necessarily picking the optimum route.

So, I guess I did do 10km in an hour - and the rest was a bonus ;-D but it's also a bit disheartening - good job I didn't check how far I'd gone earlier or I might have just said to hell with it and given up before the finish line ;-D

Anway, I'm curious - is this a common problem? Will the distance I measure get closer to the official distance once I've got a few more races under my belt? And how do I get better at planning the optimum route round?

cmmercer cmmercer

Posted

The distance calculation on a phone is not to be trusted at all. There will be a degree of extra distance covered by some weaving, but generally GPS refresh rates on a phone will not allow for an accurate measurement and should not be trusted. Even specific GPS devices will rarely be accurate as there is always an element of delay and any issues in high rise built up areas or similar. To be certified the course will have been accurately measured and the only way to hit this distance perfectly is to know the exact route it travelled (the blue painted line at London Marathon).

Poppy Field Poppy Field

Posted in reply to cmmercer

Hmmm. Interesting. I'm using an ipod nano with Nike+ fitness on it, not an iphone (no idea if this makes a difference!) which claims to be accurate to around 90%. I think I'll take it with me next time I'm on the treadmill and see if what it measures equates to what the treadmill is telling me to get a better idea of how accurate/inaccurate it is.

cmmercer cmmercer

Posted in reply to Poppy Field

I don't know how that works, but if it works on stride rate or something similar then surely going up a hill would affect distance as your stride shortens and cadence increases.

bretrunner bretrunner

Posted in reply to cmmercer

If your device you use is claiming 90% accuracy then over a 10k course it can be 10% out so thats plus or minus 1k, with the weave you will experience in a race its not beyond the realms that your device read 11.67km.

The downside for you however is that you have not run the distance you stated due to the error in your equipment.

All UKA races have to have a certificate of accuracy issued before they get a race licence, so that anyone racing has the confidence that the distance covered is the distance stated, they are accurate to within 0.1% which is plus or minus 10metres.

GPS devices and other similar devices should be used as a guide only, they will screw with your mind. I never race with one just a std stop watch.

Chubby Bloke Chubby Bloke

Posted in reply to bretrunner

Nike+ is inaccurate. Don't trust it. Get a forerunner!

Poppy Field Poppy Field

Posted

Curses! And all this time I thought I was already running 10km :-( Still, on the upside at least I actually *have* now! Am hopefully going to start going to our local park run so I can build up better speed and time over 5k. For a laff will also 'measure' it using my Nike+ and see what it tells me I'm doing!

Purple Peril Purple Peril

Posted in reply to Poppy Field

Have you tried mapping it on Map My Run? I use it for planning routes and find it very accurate. Free to sign up and use if you don't mind a few adverts.

mcboro101 mcboro101

Posted in reply to Purple Peril

I have a Garmin Forerunner its pretty much bang on all the time, the most it is out is .05 of a mile over 10k. When i run with my friend who uses his iphone its usually nowhere near the right distance. hope that helps

mh1 mh1

Posted in reply to mcboro101

Started out using nike+ now I have a forerunner 110 which is much more accurate and which I find much more useful for mapping routes etc

ibelieveican ibelieveican

Posted in reply to Poppy Field

my nano is never acurate..but what a great feeling when you think youve run 2.5miles and when you check using car mileage its actually 3miles....smugness...and the sweaty tops justified...

tim13 tim13

Posted in reply to ibelieveican

Garmin Forerunner is pretty good - maps closely to km and mile markers in races and also to "route mapping" software on the internet. +- 50m in 10K

Boothy Boothy

Posted in reply to tim13

At the end of a 4 mile race at Arncliffe last Saturday my Garmin 205 Forerunner read 4.06 miles. I mentioned this to the race organiser who told me the course was actually 100m over 4 miles, so my Garmin was spot on.

36 minutes ago