Yesterday I ran my first 10k since I injured myself two months ago. I set off on my regular, favourite route, telling myself that speed was not called for, just steady recuperative kilometres back on them legs. I use Runkeeper, because I carry my phone for music and also track the run with my Crane (Aldi) GPS watch. Both of these tracking systems have given me some odd results at times, so they are there to keep a check on one another, but I have never before had the problem that I encountered yesterday.
As I said, a steady run on a familiar route, so imagine my surprise when Annabel Runkeeper-Smythe solicitously chirps up after about 900 metres to tell me that I have run my first kilometre in 5.03minutes. She may have been trying to protect me and get me to slow down even more, but I wasn't fooled, since I knew I was running at approximately 6m/k, which the watch duly confirmed. Maybe just a blip getting started, I thought, but no, the second kilometre was announced in her caring Mary Poppins style, long before I reached 2k.
This continued throughout the run, with the difference between my two tracking systems getting greater with each kilometre I ran, although I knew from experience that the watch was giving me the more accurate result. Annabel annoyingly continued to notch off these short distance Ks for the rest of the run, consequently announcing that I had run 10k at 59:13, whereas the watch made me run another 700 metres before I reached the big One Zero at 1:04:03.
So, take heed, two GPS systems can give very different results (and Pbs, perhaps!!), while recording the same run. Runkeeper run: 10.7k: GPS watch run: 10.01k. I know this route and the watch was, this time, accurate, but I fail to understand how, when they are presumably using the same satellites and both giving fairly accurate tracks on the map, they can be so far out on distance covered.
Do we have any GPS geeks out there who can explain this? Is my phone finally defunct?
Keep running, keep smiling.