great advice from Hippo. I too, have never taken a day off for PF, I just gritted it out on bad days, cried some mornings, but refused to back off, even when my MT said "you're calves are getting so tight". A torn calf is my longest injury. I had the entire summer off and even now, I running 50-60% of my previous mileage. I'm hoping to get to 75% someday.