One thing with Martial Arts, and those like Karate, Gung Fu, it's a training of both body and mind.
When one is young, you can catch on quick, you learn techniques, by practice and repetition, and if you had gotten good at a young age, the moves are ingrained, you remember how to execute such moves, sort of like riding a bike I suppose. But as you age, the body has a hard time doing what the mind tells it to do.
They used to refer such as "visiting the Altar".
Doing forms, they are of course the building blocks. Dependent upon the style, you learn blocks-parrys, punches, and kicks.
Some hard parts are the physical hardening of the body, Rome wasn't built in a day.
I remember my Judo 5th Dan cousin once told me long before he achieved that rank the first things they learned were how to fall. Without getting hurt hopefully. I seen him once body slam himself. Got up like nothing happened. When he was 11 back in the 60's, he took a first place in State of Illinois Competitions, he was already a Brown Belt.
"Slipping Punches and attacks, yeah, you see guys like Steven Seagal slipping a punch, oh so easy, but sometimes you cannot slip a punch-attack, your forearms come into play, and they can take a beating.
My cousin once broke his forearm sparring, and taking a full force side kick, they said they heard his arm break all the way across the room like a pretzel snapped.
Like Myagi once said, "don't be there", but yeah, that level of proficiency can take many years to achieve.
That Shoalin Junior Grandmaster I earlier mentioned, that's my old RR work buddy Mike Loconti. He helped train Arlene Limas once, and before she took medals at the Olympics.
I worked out "for" Mike once. He was wicked like a Marine Drill Instructor it felt. Like I say, throw punches or kicks at people like him, you really f'ed yourself, it's like they see all in super slow motion.
They'll block a punch or kick with with the same. Like swatting at some "gnat" actually.
And the leg work with the Sweeps, man, it's like watching a deadly ballet, where I seen really big guys hit the floor head first in the blink of an eye.
And you "thought" you were going to be slick, jump in the air to avoid and defuse that leg sweep when like I say, you really f'ed yourself and set yourself up for a follow-up leg sweep and you are down and out! You just lost that fight because there was "****" (Coup de grace) coming you couldn't imagine once you were taken down.
Mastery of such then superceedes height, weight, or strength. I remember one of Bruce Lee's comments, where he spoke of "economy of movement".
Another of his sayings was "investment in loss".
Many good fighters understood this, one method perhaps could be called "Ali's Rope-a-Dope".