Before I start, I re-watched the Kill Bill old chink board break scene. The concept there is he, you know, actually punches through a fucking board. I have never seen that happen irl or in a video.
So, I have two questions here:
1. Is there any videos of anyone actually breaking some real shit? As in, not premade to break (muh tkd boards) and not carefully position on its very edges (muh karate bricks).
2. Are there any good books on breaking? I have broken concrete at tkd before, but I really have no clue wtf I am doing. It just seems it's all the way its positioned and concrete crumbles.
First you have to understand why something breaks as it does; when you strike any object, the reason it breaks is because the the energy transferred into the object does not have enough time to return to the medium it is transferred from. If an object's mass or its surface is not dense enough to halt the movement of another incoming object, it breaks. Additionally, physics shows that penetration of the surface of an object is greatly increased in relation to the surface area of the medium transporting the force, or kinetic energy. In other words, the smaller the point of contact, the more focused this kinetic energy is, enabling the object to be broken.
In other words, breaking boards and bricks and the like is little to do with strength and more to do with speed and form. The spacing you see in the picture makes it easier to break each board individually. Otherwise, with such a mass to penetrate, the practitioner would break their hand. It's more of a demonstration of application than anything - it's like a martial arts magic trick.
Now if you want to see something impressive, see Muay Thai kick drills and how people break bats. Because of awkward size and shape, as well as density, it's much more difficult to break a bat. Additionally, because the bat is broken without the assistance of gravity being applied to the object, it's all the more difficult.
See how the bat splinters? It's showing that the kick wasn't clean, as like breaking a board; there was a lot of resistance, and the execution was additionally reliant on the strength of the practitioner.
TL;DR - Bricks and boards, while take a level of practice and legitimate skill, are more of a magic trick in the grand scheme of "breaking things". It's an application of physics and nothing more. To break other items, it will take teaching on how to apply the correct strike in the correct manner and a level of self-durability and strength.
Roughly speaking, there's no magical way to learn how to break things. It will take you conditioning your body to not break when you exert its momentum and strength and an understanding on what sort of strike is appropriate for what surface. Basically mastery of the body and mastery of your surroundings.