I heard of that... It's really not a race, if it is what I think it is, it's a group event. They add a bunch of weight to their ruck sacks, if it is what I remember reading about it was sand. If you were under 150lbs it was 20lb. and over was 40lb. and then it was a long hike (like 20 miles?) for your team. And you only finish if your team does.
"An unarmed man can only flee from evil, and evil is not overcome by fleeing from it." -Col. Jeff Cooper
"An unarmed man can only flee from evil, and evil is not overcome by fleeing from it." -Col. Jeff Cooper