I was in the Navy and I used to go to this PT for people going to Special Programs (BUD/s, Diver, EOD, etc...) We regularly PT'd with a SEAL (Senior Chief Macintyre (spelling?)).. He was a cardio/PT maniac... Anyway, the hardest PT I ever had was when this crazy little Diver Chief fuk'n smoked our ass. We must have done 1000 chest exersizes before he had us bear-crawling around the track... Back to another superset of chest and then back on the track... For those of us that couldnt move via the bearcrawl anymore, we were allowed to line up on the opposite side of the track from the bearcrawlers. "OKAY fellas (evil looking smile on his face) , bend over and loop your pointer finger through your shoelace (the one closest to your toe, left hand-left foot/right hand-right foot). All you gotta do is walk around the track.." I should have known that it was gonna be worse than the bearcrawls... DUMMY.. Im 6'1" with long legs proportional to my torso. Im good at running/swimming but suck at stuff like squats... It might not be bad for shorter guys or people with strong/powerful legs. Its super easy at first but all of the sudden your body locks up and doesnt want to move. Just try to make it around the track. Give it a shot and tell me what you think.