Featuring the proven 80/20 intensity balance described in Matt Fitzgerald's bestselling book 80/20 Running, this marathon Level 3 training plan will provide you with the same workout structure used by the most successful runners in the world. TARGET ATHLETE This plan is designed for experienced competitive runners who are prepared to train 2x a day some days in pursuit of a Boston Qualification time. Before you begin the plan, you should be running at least 3x per week, with short efforts at ...