Naruto Twins Experiment

I always wondered how the scroll on these twins back always stayed up. And since it's in the back, does it support Ukon in a way? And since I am oblivious to all means, I didn't really see how they hold their scroll up on their back or even if they use it at all, so the question I asked was, does the rope help?
Maybe I need to start paying attention to details on a character if I wish to ever draw them.