Stick 6km/hr on the treadmill and it's a slow jog. But one you have to average over 90 mins, where there's alot of inactivity (ball is in play for about an hour). For some one relatively fit it's a breeze. No problem at all. But what I'm suggesting is that there's alot of exaggeration in these watches due to the way they gather their data. The best way to begin to understand their accuracy is to start of with your own fitness and see if you are capable of doing the distances suggested by the technology. I've seen people suggest they're doing 9km, when it's absolutely as clear as day that they aren't physically capable of that.