Do these hills every 5-10 days, but don t ignore the other elements in your training. When you can handle hills well in your marathon training, they will seldom be a problem in races. Tuck in behind someone, get pulled up the hill, then find that other gear you ve been practicing as you accelerate over the top. Hills will improve your marathon racing speed by building strength in the quads, hamstrings, buttocks, calves and back. Hills increase your anaerobic efficiency.
Bigger quads result in fewer knee injuries.
Doing a lot of distance can decrease your stride length. Even though you will be doing repetitions, 200s etc. Just remember to exaggerate the knee lift and the arm swing, while pushing off with the toes and calf muscles. The high mileage person should be able to go straight to the 10 or 12 x 400 meter hills. The low mileage beginner will start with just a few reps at 100 to 200 meters.