Source: Roy Johnson / Fit! Live! Win! First and most importantly, Dr. C, ask your doctor if you're healthy enough to race. Presuming you are, congratulations! By signing up and taking on the challenge, you've already won! This morning at the gym, I asked a friend who's a runner how she would recommend someone prepare for a 5k (3.1 miles) or 10k (6.2 miles) race. The key is working your way up to the distance, giving yourself enough time (at [...]