I currently use a mixture of Nike+ and RunKeeper GPS app (on my htc desire phone) to measure distance outdoors and I get very different results.
I guess RunKeeper is more accurate and I use a strap ontop of my trainers for the Nike+ rather than having the Nike+ trainers, maybe this makes it less accurate? When I try to calibrate it comes up as distance doesn't match!
Also, on the treadmill in the gym I can't seem to run anywhere near the distance I think I do outdoors in the same time.
On the treadmill I struggle to do 2.5k in 20mins whereas I know I can complete a 5k race in ~30mins and when I up the speed it's a real struggle to keep up the pace! Plus if I wear my Nike+ I get completely different results to what the treadmill says and obviously can't wear GPS to check.
I'd like to start training for my first 10k race in May and would really like a accurate way of recording the distances of my training runs!
Any thoughts/advice would be most appreciated!