god only knows why you would induce a cramp in your legs. all i know is that when i ran in high school and i got a cramp anywhere in my leg, specifically hamstring or calf, i had to take a couple days off. my teammates would all do the same, and so did kids i used to run against. as far as i'm concerned a cramp does more harm than good.

last real cramp i got was junior year in my right calf, i had to take off about 5 days and then start back up running easily again. i could definitely feel the residual effect.