Meh, you should run at tempo. If you don't push yourself, you won't be able to keep up the program and will end up repeating weeks. I did the c25k program, and I did it on schedule because I pushed myself. It kinda sucked...like all exercise kinda sucks in a way (what I mean is that I love it, but it's not exactly comfortable if you do it at the appropriate intensity.) But then you get better, and that should be reward enough. Unless this person is over 200 lbs, in which case s/he should lose some weight first so she doesn't get hurt.