I am using Nike+ on the iphone at the moment. Its says I'm running 450m in 2:10. This is ridiculous, even if I am a beginner. I remember running a 13s 100m when I was 12. The most I wouldve expected for the 400 was 70s. Yes I was slowed down by a car and ran up a small hill, but how accurate are these apps in your experience? I will run at the local track soon to find out.