I have known these type of guys before, the black belts, etc. and after you put a cement block in an oven and remove all the moisture, they are not hard to break and their secret to breaking stacks of blocks is to place like a pencil or object so each block has an air gap.
They focus allot of energy and flex the muscle only at the time of impact and they can make for some impressive shows, etc. But there is always a gimmick envolved, certain laws must be obeyed and the more spectacular the show, the more the performer must obey the science.
Muscle/weight helps, but by no means is an example, because the thin light weight that has better control, can put on just as big a show as the person with bulky muscles that has the mass behind his blows.
For the spoon guy, I would never believe it until he bent a fork I gave him, because these guys have been proven as fakes along time ago.