Is it true that if you keep hitting your bone against a hard surface, it cracks, but becomes even denser?

Question

This strongman I talked to can break through like 10 concrete blocks, and even this thick block of ice. he said that his bones don't shatter because he's been doing it for a long time, and that they're stronger than say, my bones.

is it true bones can be injuired through high forces (like hitting em against ice) but heal stronger somehow?

Answer 1

There's two different things you're discussing here.

1) Yes, if the bone fractures and repairs itself, that area is now stronger than it used to be. Other areas of the same bone is still the same strength and can fracture around that healed area.

2) Under stress, like exercise or breaking thin wood boards, you can develop stronger bones. No stress results in weaker bones. Gravity is one stress, hence the need for astronauts on the space station to exercise otherwise they can lose up to 30% of bone mass. Martial artists can break concrete blocks because they've been breaking wood boards over time, increasing bone density where it can withstand the impact of breaking concrete. They can also break metal bars too. I believe either History channel or Discovery channel covered this exact material, where they showed the bone density of a skilled martial artist was 2-3 times as thick as a normal person in the fists.