14 Week Winter Running Plan Base phase: 5 weeks Aerobic Development phase: 6 weeks Race-Specific Introduction phase: 3 weeks Base phase builds from 8 miles per week to 15 miles per week. Aerobic development builds from 12 miles per week to 20 miles per week. Race-Specific Introduction phase maintains at 20 miles per week. Down weeks built into training schedule. This plan is built for a relatively inexperienced (1 year or less of running experience) high school runner looking to prepare ...