A complete 14-week training program to help the runner complete a half marathon. This program (LEVEL 13) is perfect for the athlete who has completed a half marathon before, is used to a little more mileage during the week, and wishes to improve on his or her personal records (PR's). The runner will download a detailed PDF training calendar with a helpful description of each scientifically designed workout. This particiular program assumes that the target race day is a Sunday, and so has all long runs scheduled for Sundays. Mondays are considered "off" days.