Our Intermediate Marathon Running Plan is 20 weeks. It is designed for runners ready to advance their endurance and performance at the marathon distance. Quick Overview: - Duration: 20 weeks - Runs per week: 5 - Key/Hard workouts per week: 2 - Cross-training days per week: 2 - Smart device structured workout compatible - Geared toward experienced runners at 10K, Half or Marathon distance Weekly mileage = 20-50 miles per week (weekday runs are based on duration so actual mileage may vary. ...