nit: 6.75 is a run for a lot of people. It's even a sprint for some. 4mph is a very, very fast walk for a lot of people. A "becoming healthy" 5k (3.1-2) time i

nit: 6.75 is a run for a lot of people. It's even a sprint for some. 4mph is a very, very fast walk for a lot of people. A "becoming healthy" 5k (3.1-2) time is 30 minutes, which puts the runner at more than 6 miles per hour. A friend of mine is returning to health, and he was winded after a 30 minute walk at 1.8 mph the whole time.