This is ice diving with people doing a rather tricky job of walking upside down on the ice. It is much harder than it look. Imagine where the center of gravity

This is ice diving with people doing a rather tricky job of walking upside down on the ice. It is much harder than it look. Imagine where the center of gravity is when there are a pair of lungs with air (expanding and contracting), and a bunch of weights where the tanks are. Inside the suit there is also free moving air that want to rush down to the feet, and air tramped by very heavy clothes inside the suit. On top you are standing on the very even and slippery waterside of the ice. The gear is also designed towards being weighted so you get a nice trimmed horizontal profile, and so it really want to tip over when you are doing something like this.