Case in point: writing. Writing is a cerebral activity. The story starts in your brain, germinating like a seed as you work it out. Some writers are outliners; they always write the outline first; some are pantsers (they just start writing "by the seat of their pants"). But all kinds of writers use their brains to create their stories. The process of getting the words onto the page (or screen) happens slowly or quickly, in spurts or steadily, and continues until the story is born. Then the work begins: revisions.
Reading your own words and seeing where they need revising takes practice, too. In some cases, the surgery is drastic. Plot lines, sub plots, characters may be cut to shreds and then be reborn looking entirely differently. In other cases, the surgery is cosmetic— snip a word here, tuck in a line there, change a name, leave out the tag lines, tighten the description, and you get a much cleaner, smoother story.
The more stories you write, the better you get at writing, just like playing basketball or working crossword puzzles. If you take a break from writing, it can take a while to get back into the swing of it, like dance steps you've forgotten. But once you practice the steps, the dance becomes comes back to you.
And writing is a fun dance. I enjoy writing. I wish physical activity were this much fun. I would be so much thinner!
Sadly, the brain is a muscle that burns no calories.