Hal Higdon: 15-K-Intermediate: The following schedule is for Intermediate runners: individuals who want to improve their 15-K performances. What defines an Intermediate runner? You should be running five to six times a week, averaging 15-25 miles weekly training. You probably also should have run one or more races at distances between the 10-K and the Half-Marathon. With that as background, you now need a somewhat more sophisticated schedule so as to improve. Each day, I will send you an email telling you what to run and also offering tips about training. For more information and directions, visit my website: halhigdon.com.