A writer must be able to understand their protagonist inside and out. She has to have an instinctive understanding of every character she develops. Basically that means, walking in their shoes before she gives them shoes. It's being aware of what motivates them and why. Understanding why they feel the way they do, and what makes them who they are. For me, I try to imagine what type of games my characters play, then I attempt it. I say "attempt" because my knee replacements are not bionic. Skipping rope or hopscotching are not an easy task for me. However, I can slowly go through the motions. This allows me to imagine my character's embarrassment when she trips over the rope while trying to impress the boy across the street, or the joy a little girl feels when she finally makes it to the tenth square in hopscotch.
A writer also needs inspiration. So, what better way is there to gain it then feeling the wind in her hair as she flies high in a swing? Or, lying on her back in the middle of a playground merry-go-round as it spins out of control? Or, chasing fireflies through the forest just after dusk? Inspiration is defined as the process of stimulating a creative action. For children's writers who are in dire straights to stimulate some creative action, a few minutes of actual play may be the answer. But there is also another reason play is essential, it increases your perception.
To write for kids, it is necessary to have a split personality. One side is the adult who crafts the words so they flow into a cohesive story. The other side, however, is the child protagonist or antagonist who makes the story believable. It's that side of the writer where play is essential to perception. Play actually helps the writer recognize, understand, and appreciate what the character is feeling through his or her senses. When writers are thoroughly aware of what their character is hearing, seeing, tasting, touching, or smelling, it naturally flows on to the paper. It's not stifled or stale. It's full bodied and exciting. But there is one more reason writers should play.
It's fun! So quit reading this and head for the playground. Nothing gets the creative juices flowing faster than a ride down a slide. That is if you can still climb those narrow steel stairs.