Hollow-arch shape conditioning with resistance band

I saw this a while ago on a French tap swing/giants video; finally got around to trying it out when I saw the right kind of resistance band lying around in the gym.  This is the first time these two gymnasts have tried it out for me. 

It might make for a fun (until the novelty wears off) hollow-arch conditioning station if the girls understand the correct action and can safely get in and out of it on  their own.  Done right, I would think they should feel it in their arms, upper back muscles, and abs/core- especially if they can pause it in the back.  it might also help stretch the hip flexors and with leg tightening.

Here's where I got the idea, a minute twenty-one seconds in:

A lot of good content in there.  Also in some other videos on the channel.