I found this short video on youtube of a child kneeling. I am impressed that she is so cooperative given that she needs to work really hard to control her trunk.
I can get several of my kids into a quadruped position while grasping the handle. Its very exciting when they will grasp my hand (and the sidewalker's hand) to hold a kneeling position. It looks like the facility in this video has the same problem I have- a small arena with a lot of walking around curves. I wish I had an indoor with long straight lines to practice challenging positions such as kneeling before doing them on curves.