Long days of hiking really take their toll on an athlete’s body. Most ultra-runners would not fill their diaries with too many ultra marathons (a distance greater than 42km is considered an ultra) in one year, as it is so hard on the body, and takes a long time to properly recover. Yet it is not uncommon for athletes in the Red Bull X-Alps to hike multiple marathons in one day, and there is precious little time to rest and recover before having to do it all again, for twelve days running.