Awwwwww... Ruby is adorable!! Love that little video! Willie is about four now, and a big boy, and he still gets the zoomies. He runs in HUGE figure eights out in the yard. It's not a small yard, either. I think he just likes the feeling he gets from running the figure eights. Always follows up with big drink of water.
When Dexter was that age we were in our motorhome for the summer. He would run from one end of it to the other, back and forth just like Ruby. It was much fun to watch as long as we stayed out of the way. By the time we got back home he had mellowed considerably. Thankfully Scarlet was never like that because she could play with Dexter outside to get the energy out.