hitting the heavy bag

“I was hitting the heavy bag, doing as I had been taught, throwing fast, loose karate punches and tensing them at the moment of impact when Mac said, ‘You realize that's unnecessary, right?’ I was flustered. It was the way I was taught. I hit hard. I started to argue and explain. Mac continued, ‘All you need to do is get these bones (he indicated my metacarpals) in line with these bones (the radius and ulna).’  Then he completely shifted my understanding of martial arts ‘Tensing and clenching are what people do when they don't understand structure.’” - Rory Miller, Chiron Training, Concretes and Abstracts

Comments: Uh-oh, an Oh-SHIT moment reading this one. Notice that his lessons involved the application of physiokinetic principles called structure, alignment and others?