14 Week Marathon Plan: Finish Proud & Strong (Your base should be at 1.5 hours on the weekends. And not injury-prone for this marathon plan.) Target Audience: Runners who have completed at least one marathon & maintain a consistent base mileage (25 miles per week). This plan will build from (5hr to 8hr) 25 to 50 miles over 14 weeks. You will be introduced to challenging yet fun workouts.