Obstacle Run is a high burn aerobic workout that requires great body strength and endurance to pull off. Do it at Level III with minimum rest between sets and you will be pushing against the boundaries of your endurance no matter how fit you are. It's designed to get you into the sweat zone from the first set and done at the maximum of your ability, with no holding back it certainly will make you feel the burn.
Extra Credit: 1 minute of high knees non-stop, no pauses.
