Thanks Scrap I really do find this stuff fascinating and can't wait to give it a go!

I was going to write more but my stupid internet connection dropped out.

Anyway I'm guessing you do it both with the band in front and behind because falling backwards is as bad as falling forwards. The big circular band exercise looks like it might stretch the muscles down your side under your armpits?

I know this area can get tight and can be awkward to stretch and so it that's what it targets that's a bonus! I think when i get tight there it seems to make me hunch a bit so I think they're posturally important.

Also working some muscles in the hips there. I'd need to sit down with a few books to work it out which ones ..... I'll keep studying