Today I did a 5 mile test run, using both my Garmin Forerunner and the Nike+ system. I also entered the run info into My Food Diary. Here are the results from the same exact run:
9:28 per mile
8:59 per mile
My Food Diary
742 calories (at 3% incline)
558 calories (at 0% incline)
So are Nike miles longer than regular miles? I don't really know! To be fair, there are two things that could throw off the accuracy of the Nike system: 1) the way I have the sensor attached, there's a good amount of "play" which could throw the readings off, and 2) you can calibrate the system in some way that I haven't taken the time to do. And when it comes down to it, it really doesn't matter what the numbers say, as long as you're moving in the direction of your goals, right?
But I kinda want to figure the discrepancy out, ya know?