I'm always amazed at the level of physical endurance those people compete at.
100 people start each challenge
there have been 20 challenges so far.
So out of 2000 people who have tried only 3 have completed the full obstacle course.
If you've never seen it, here is a sample of the obstacles they have to go through.
http://www.youtube.com/watch?v=lJmCem8qbTEPlus the commentary is hilarious at times.