I see fighters like Masaaki Noiri or yuki yoza and just seem to never break like shots that land don't even affect them meanwhile I gotta take a break if I take a clean roundhouse in sparring.

I don't get it, whats the secret because I train my core, have they just been hit more than me so they're body's used to it, does the nervous system play any part in this because they look so relaxed and calm in fights.

If anyone knows it would help to share.