Mark Thornberry, 57, was diagnosed with liver cancer. Now he's running ultras to help raise funds for cancer research at his hospital.
A guide to running your first 50K including key intensity workouts and a free 16-week training plan.
Jason Koop explains why almost anyone can finish an ultramarathon.
Where does training go wrong for ultras?
Check out these awesome shots from a muddy day in one of America's coolest national parks!
What you need to know before you go.
Check out these awesome shots from one of the country's most competitive 50Ks!
Enjoy this 22-minute documentary by Los Angeles-based filmmaker Billy Yang, who chronicled the adventure.
The announcement comes after two recent uproars surrounding convicted dopers.
A conservation group founded by National Geographic Emerging Explorer Gregg Treinish has recruited ultrarunners to help search for