Looking at it again, and again this time, could it be that he has a prosthetic left leg below the knee? A coworker of mine had one, and it always looked like he had a rhythm when he walked -- a type of a little swing when he walked. It just struck me, seeing it again. And, believe it or not, he could run with the prosthesis -- no problem. He admitted that he had practiced a lot -- he had a "sport" prosthetic which he wore every day -- he had been a jock in HS & college. Just a thought.