Running 50 miles for 50 days Red Bull Human Express

Check out more action here: Ultramarathon runner Karl Meltzer will embark on his attempt to cross the historic Pony Express by foot. He will cross the Rocky Mountains and the Great Plains from Sacramento, California to Missouri relying solely on his wits, athleticism and endurance to push the boundaries of human potential. Keep up with Karl at Experience the world of Red Bull like you have never seen it before. With the best action sports clips on the web and original series, prepare for your stoke factor to be at an all time high. See into our world: Red Bull on Facebook: Red Bull on Twitter: Subscribe to Red Bull on Youtube: Subscribe to the Red Bulletin: Sign up for our Newsletter here: