Every October in Tennessee a race is put on by Lazarus Lake (Gary Cantrell) of the famous Barkley Marathons. It is a 4 mile an hour loop until one person is left standing. 3 years ago the race went 49 hours until the 2 guys still duking it out dropped at the same time. They went 204 miles in those 49 hours. Check out the race at this link:
Big Backyard Ultra - October 21, 2017
Big Backyard Ultra - October 21, 2017