Many marathon runners think that they have to run 100 miles a week to compete successfully, but most will be able to run a marathon faster if they run fewer than 50 miles a week. Top marathon runners can run 100 miles a week and not be injured because of their superior genes. When most runners try to run 100 miles a week, they run too slowly in practice, and as a result, run too slowly in races.
To be able to compete successfully in any sport that requires speed, you have to train at a very fast pace. For runners, training at race pace or faster is far more important than how many miles they run. However, it takes time to recover after running fast, so most top runners are able to run very fast only once or twice a week. Most top marathon runners run very fast twice a week and long once a week. These three workouts form the basis for their training. All of the other workouts are done at a slower pace and should not be so fast or long that they leave you too tired to get through your three important training workouts.
A typical training schedule for a top marathon runner includes two workouts a day on weekdays and single workouts on weekends. They run very fast on Tuesday and Thursday afternoons and long on Sunday. They run at a slower pace on weekday mornings and Monday, Wednesday, Friday and Saturday afternoons.