Can't see the link Lexie - just copy the address bar on youtube when the video is playing and paste that in your post and it should link.
Here's Charlie running in his Flying Saucer. He runs much better than this when he's running in it, but in the video he is trying to climb up it to get over the top of the playpen (this was during his very active period after we came back from holiday), so he is running bent instead of straight for part of it.
https://www.youtube.com/watch?v=iFOEsqlmj88