Stop running your easy days too hard and your hard days too easy. Tackling 31 miles requires safely building a massive aerobic engine without injury. Designed specifically for beginners taking on the 50K ultramarathon, this 26-week (half-year) plan uses the proven 80/20 Endurance methodology. You will run 4 days a week, with 1 day of alternating low-impact cross-training and power hiking. This keeps the vast majority of your miles purely aerobic (Zone 2) to safely build time-on-feet and trail ...