We’ve all seen the videos…a person wearing a white uniform and a black belt stares down their opponent; a stack of boards six inches high. They take a breath in, and — wham! — their bare hand whips down and breaks the stack cleanly in half. The broken boards tumble to the ground, and the breaker walks away triumphant.I know what you’re thinking. “I’m not powerful enough to do that, forget it! I’ll just watch. Why would I need to…