Why do Japanese wrestlers go so hard in a way that destroys their bodies by the time they’re 40?

You see it with so many guys. Naito and Tana are the prime examples of the last 15 years or so, but you saw it with so many of the older guys too.

It's primarily knees right? I know Kobashi was the same

What is it specifically about Japanese guys where they just absolutely RINSE their bodies?