This is a video showig the science of breaking bricks and blocks with the body, actually constantly traing your body makes it harder and tougher, continually challening yourslef you turn from soft to hard. Smashing the normal persons bones a well trained expert can generate more power than a sledge hammer blow.

About 8 mins in to this video  “what the Fuck”  the Spear. Them bricks got pwoneed , dammm!!