Featuring the proven 80/20 intensity balance described in Matt Fitzgerald's bestselling book 80/20 Running, this Ultra Marathon 50 Mile/100 Kilometer Level 1 training plan will provide you with the same workout structure used by the most successful runners in the world. TARGET ATHLETE This plan is appropriate for newer runners preparing for their first Ultra, masters athletes, or for more experienced runners who need or prefer a relatively low-volume training program. Before you begin the ...