These days in exercise, cross training seems the discipline we're pointed towards to make sure we do some all round exercise for our bodies. In the last couple of years I've seen it put forward of a way to improve, stimulate or generally make more satisfying our meditation practice.
I'm not sure that I'm sticking to the theory behind this advice in meditation but I do know that if I alter practices occasionally, say every few months and then circle back to the previous one, I seem to have gained more depth in the one I changed from.
How can we use cross training in writing?
Years ago when I was taking business writing courses I met a writer whose output was phenomenal. It was joked of him that he could get in a lift and by the time he reached his floor he'd have written a successful promotion.
When questioned he said the secret was simple. All writers get stuck at some time in what they're tackling. He'd found the best way to avoid that was to work on as many projects as possible at the same time. If he ran out of ideas for one project, he didn't bother to struggle, he simply moved to something else and by the time he went back to where the obstacle was, hey presto, more often than not, he knew exactly how to deal with it.
I've used this approach for many years and depending on what you're writing it can work. Writing a novel and get stuck - try short stories or poetry instead. Writing non-fiction and get stuck - write dialogue and it really helps make your factual work easy to read.