Interesting thoughts on his back and all, however, the hang clean is meant to be a violent exercise, just as it would be during a game. His form is pretty damn good for 400lbs!!!, you have to admit. The heavier the weight, the more difficult the technique involved. In a game, he will be able to use the same movement on a 290 lb defensive end, theoretically, with far greater ease. Also, Coach Doyle is one the brightest minds when it comes to activating your core muscles. Someone would definitely ruin there back doing this without biulding their core muscles built up. Unreal couple of lifts thought... wow.