flying crane said:a few comments here...
I don't believe the heel-up stance he is using is the best way to deliver torque power or twisting/rotating power. Feet down and planted gives your feet the ability to drive against the ground and really get the full torque of the body. But the feet and legs really need to actively engage in driving the strike. Just standing or stepping on the feet and twisting the upper body doesn't really do it. Drive from the bottom, don't twist from the top. Instead, he is really throwing his body weight into the strike and I do not believe it is really torque. He might be getting the torque to some extent, but I don't believe it's as much as he might think.
also he shows another common mistake made by many people: he doesn't quite match the strike with the movement of his body. His body stops moving before his strike lands and this robs the strike of much of the torque potential.
also: he seems to only use the torque on the one strike. Why not use it on all strikes? In his blocking, torque punch, knifehand combo, why not use that torque on the blocks and knifehands as well? Those strikes look like he's really only relying on arm strength.
another thing: when doing his torque punch, his torso is slightly bent over. This throws his center of gravity off, and robs him of stability and power. Torso should be upright for maximum potential in this kind of strike. Otherwise, again, he ends up throwing his body at the opponent, which is not torque.