In an ideal runner's world, every step of every mile would be 100 percent pain-free. No aches, no twinges, no lingering soreness from yesterday's workout, but then everyone would do it. One article that I read last night stated that 30-50% of runner's will incur an injury in a training year!
Most common running injuries:
plantar fasciitis - an inflammation in the bottom of the foot. The common characteristic of this condition is a sharp, painful sensation at the base of the heel that can be anywhere from annoying to excruciating.