Whether you’ve already ticked off a few marathons or are a newer runner with big goals from the outset, stepping up to a 50-mile race is a powerful move. It’s a gateway into ultramarathon territory — a tough but manageable leap that will challenge your mind and body without tipping into the truly extreme.

This 16-week training plan is built around your threshold pace to define your running zones. It focuses on steadily building endurance while strategically incorporating faster-paced efforts to help you maintain speed, strength, and power over the long haul.