If i join a Nike running contest after the starting date does my miles count from the start date?

Say if the start date on a Nike+ running challenge if 1/1/10 and i start it on 2/5/10 but scene the start date i ran 150 miles does my 150 miles count towards the challenge or do my miles start after the day i start the challenge.|||I think it depends on when you buy the chip and download it. I would think that if it starts on the first and you start the 5th of February you mileage begins there unless you have it on your ipod.|||I would guess the miles count from after you join the contest