Is this that different from any other weird martial arts stuff? Like, I broke boards in karate classes as a kid. It’s just a dumb fun demonstration that kinda looks cool and looks more impressive than it actually is. They’re made to break, and if you do it correctly it doesn’t really hurt. And that mostly looks like concrete, which isn’t known for standing up well to that kind of force. Suspend a thin slab of concrete like they do here and I bet you could do the same thing - Concrete breaks really easily.