While trying to get them to crawl through the spinning tube, they at first seem apprehensive. She tells them to crawl several times and the little girl decides to go first, although I don't think she heard the instructions correctly. She sits on the edge on the tube and holds on with her hands. Next thing you know she is completely upside down, still sitting like nothing is wrong. That is strength. It also takes a few moments for mom to notice that her daughter is going completely upside down.
Once her daughter is safe, she cannot stop laughing. I'm still in shock over the strength of that girl!