>>11155432From what I've read on this the spine is mobile even though you can barely flex it. And there's two things that are preventing you from assuming a normal posture.
1) The length of muscles. You need to spend long periods of time, at least 30 minutes daily, in a stretched position to grow sarcomeres or something like that. If you want your results to be easily maintained you need to spend a small minority of the time hunched over so the opposite muscles can shrink in length.
2) Your nervous system. Your brain actually stops you from stretching your muscles too far to prevent injury. The way to correct this is the same as you'd fix muscle length, as you spend more time in extended positions, your brain moves the threshold. It's even faster if you load your muscles in these extended positions, which is how PNF stretching works.
I don't know about hanging from a bar. But one time I put a piece of plywood on my bed and used my PC laying supine for long periods, nigger rigged on a monitor arm. Eventually it got more and more comfortable over a few weeks as my head and neck relaxed, and I was about to start adding pieces of foam roller to get some positive arc but I got tired of my nigger rig as it couldn't be converted for sitting unless I took it all down.
