I’m glad you asked. The answer is, more than you might think.
I wrestled all four years when I was in high school in Huron, Ohio, and during my first year of undergraduate school, at Brown University. During that time, I learned that wrestling requires enormous dedication, self-discipline, and conditioning. Also, that stepping out onto the mat as a young adult, to face an opponent one-on-one, calls on all your reserves of courage and poise. And that in the long run, the experience goes a long way toward developing self-confidence. (I was a pretty shy kid, really—kind of geeky, afraid of girls, and not terribly good at sports in general. This sport represented a major area of growth for me.) Coached properly, wrestling also develops a sense of good sportsmanship, respect for the opponent, and the ability to win and lose with equal grace.
Writing, for anyone who hopes to do it professionally, requires if anything even greater dedication and self-discipline. My wrestling experience probably did more to prepare me for the long, tough haul of making it as a writer than any other single thing I did as a student, including taking writing courses. As an aspiring writer, I put in endless hours of work with zero promise of reward, only hope and determination. Like just about all new writers, I met setback after setback, and had to choose between quitting or plugging ahead. (This process is ongoing, by the way. It doesn’t just happen to aspiring writers. There are lots of professional writers out there, including me, who are engaged in an ongoing struggle to keep their careers alive and healthy.)
Courage and poise? Well, for a lot of people, putting a manuscript in an envelope and sending it off, unsolicited, to a publisher takes about as much courage as stepping out onto a mat. And you have to learn to lose with grace if you’re going to make it in the writing business. The poise and the self-confidence come with time. And come in mighty handy the first time you step up to a podium to speak to an audience as a “guest author.”
(Momentary digression: if you’re unfamiliar with the sport of wrestling and think I’m talking about anything even remotely related to the stuff they show on TV under the name “professional wrestling,” no. Don’t. No resemblance. Don’t even talk to me about it.)
A surprising number of wrestlers turn out to be good students, as well. Maybe that shouldn’t be surprising; the same self-discipline comes into play. Some pretty well-known writers were also wrestlers. And also some less-well-known writers.*
Here’s a short SF story I wrote about wrestling, originally published in the anthology Warriors of Blood and Dream, edited by Roger Zelazny. It’s called Shapeshifter Finals.
Here are some books by wrestlers-turned-writer:
*It pains me to acknowledge it, but a well-known thug who is also our current Secretary of Defense was also a wrestler and coach. Oh well, no sport’s perfect.