The rest of your post is O.K., but it actually is possible to bust real cement bricks with just your fists, or your head, or other body parts. What happens is that after repeated striking a hard object, your bone gets stronger, and your body puts more calcium in the bone, over time it actually is possible to get your body strong enough to break bricks without using "dummy bricks" or bricks that break easily. There was a martial arts show on the National Geographic Channel, where they measured the force put out by a man breaking bricks with his fist, and compared it to breaking the bricks with a sledge hammer, and the man with only his bare fist actually generated much more force than the sledge hammer.