The Nike+ipod needs to be calibrated

Does anyone reading this, Eric, know if running with a Nike+ipod on an indoor track can wreak havoc on the sensors ability to accurately measure distance. I ran on an indoor track and the further I ran, the more off the distances got. I think the distances were never quite perfect, but they were really off tonight. Like I think I ran 4 miles and the iPod thinks I ran 4.7 miles. I think it's time to calibrate the thing. I'm going to see if I can run around Lake Nokomis because they have the mileage posted there. I knew I wasn't really running 9:00 miles. I thought it didn't seem right that I magically got that fast. Sadly, it means I have a lot of work to do to be able to run a 10K in under 1:00:00. Maybe this won't be the 10K I run that fast, maybe that will be the next one. I'm still looking forward to the Milk Run. My goal is to run it in 30:00. I think I need to pick up some speed to run it that fast.