Writers need to keep exercising just like Carl above if they want to come out on the top end of the writing totem pole. So, how do you do that?
You write consistently. Writers who write something once a month are not going to keep their skills as sharp as the ones who write daily. We read in books on the craft of writing that we must do it every day. That doesn't necessarily mean that you need to do it for several hours every day.
On the contrary, even a short 15 minute exercise per day will keep you in shape. Sure, some days you'll be on a roll and spend a few hours working on a project but on other days, you either are too busy with other things or aren't inspired to work on a long essay or story.
For me, blogging is my way to keep writing every day. I may not be writing a story to submit to an editor or contest, but I'm writing. I'm using my creativity and keeping my writing skill honed Monday through Friday every week. Most of the time, I write something on Saturday and Sunday, too, but not always. Hey, everybody deserves a day off now and then.
I also think that reading about the craft of writing on a regular basis helps keep you on top of the game. Like all fields, there are trends in writing and every writer should make themselves aware of what they are. When I was writing a lot of children's stories, mood pieces were big, and then suddenly one day, that was over. There are times when social conscience stories are big in children's books and then other times when just a good, entertaining story is sought. As a writer, you need to know about these changes.
You need to read about the changes in publishing, such as the move from print to ebooks that is happening now. You can always benefit from reading marketing newsletters and books by writers about writing.
Be consistent in both writing and reading about writing and you'll have arms just like Carl before you know it.