: "Hills are speedwork in disguise" Frank ShorterThe Fear: Hitting the WallThe Fix: Go Round it"Energy gels didn't exist when I was racing in the 1980s," says Rainsberger, "so runners were falling apart all the time. The body runs out of stored glycogen

."Liquid or solid? Energy bars, gels, and drinks all supply much-needed carbohydrates before, during, and after those long runs you'll be doing this month, but which is best? "The harder you're running, the more blood is diverted from the stomach to the working

. By not taking in carbohydrate drinks or energy gels during the run, you're giving your body no choice but to go to fat-burning. You will feel fatigued near the end, but that's necessary if you want to get stronger." Should you try it? Don't go out