We all know that breaking boards and bricks is the central, most important part of Karate. This article appeared in New Scientist in the U.K. in the 70s and I actually remember it (with what would now be a bit of an inappropriate cartoon accompanying it!). It’s surprising how much more force concrete requires to be broken, but then that’s why they make skyscrapers out of it rather than timber!
Karate physics: How your hand can break concrete without breaking itself
In karate, your hand has the power to split wooden planks and demolish concrete blocks. Physicists explain how this doesn’t also break bones.
bigthink.com