A 50K is your first step past the marathon, and the difference is smaller in distance than it is in everything else. You will be out there longer. You will need to eat properly rather than take a gel or two. On most courses you will hike some of it, and hiking well is a skill rather than a fallback. These 24 weeks build all of that alongside the mileage. You run 5 days a week. An easy run, a medium long run midweek, a recovery run, and the long run on Saturday with a short recovery run on ...