I haven't been sure, however, that this idea resonates with writing practice. When I worked as a writing center administrator, I tended to find that people who insisted they had a lot of "needs" that had to be met before writing were people who didn't get much writing done. ( If you "need" to clean your office, make a cup of coffee, read one more article, and review your notes before writing--well, that's a whole lotta wind up that's using up a whole lotta your writing time.) So, I'm a little skeptical about that kind of warming up, though I think gathering these materials for the next day, after doing today's writing is a useful part of the cool down process that helps you be ready for next time.
Instead, an idea that has been exciting me lately, and which I am trying to use for lesson planning as well as writing is to use writing itself as a warmup. This idea comes from Robert Boice's book, Advice for New Faculty Members. He recommends doing a little freewriting/prewriting first, a little messy pump-priming to get going and get creativity and focus moving. To me, this resonates much more strongly than office cleaning or reading notes--if you want to do full wheel, start with a little Camel pose; if you want to write and article, start in messy brainstorm posture. In each case, the beginning posture is not so scary as the full expression of the posture, but it's opening you to safely move in that direction.