after some time I had problem that required a restart of the mobile. After RunGPS start I loaded the training from the training log. Following this the frist few minutes the readings were completely off. I ran at speeds of 320km/h and suddenly added 20km to my distance.
This is not the first time this happened, I actually think it never worked properly from the start. I noticed in the past that it took a while for RunGPS to show that I was moving, so I always wait for the speed to be shown before resarting the training, but this time it went completely berserk.