I've often heard of people who do mental activities better when they are in motion. The eminent late physicist Richard Feynman used to say riding a bike helped me to figure out complex problems. Einstein always wondered why he got his best ideas while shaving. And Steven Spielberg has said that inspiration comes to him when he is driving on the freeways of Los Angeles.
So movement enhances thinking. My son used to fiddle with things while solving math problems. When I finally realized this was actually helping him, I refrained from telling him to stop fidgeting.
I don't know how she manages to avoid tripping while walking and reading at the same time. As for me, I've got some work to do in this moving and thinking activity - first I have to perfect the art of walking of chewing gum :))