Getting your back to bend deeply back is not an easy task, and if done incorrectly, could result in injuries. I know from personal experience. So here are my tips on how to get there one day without harming yourself.
The most important thing is to listen to your body. Know where your limit is. Go further than your comfort level, but don’t go past what your body can handle.
Secondly, take your time. This is a process, a journey. Don’t be in a rush. You will get there eventually. Think of it as slowly waking up your back so that it can be limber.
Now, alignment. The most important physical cue I have learned is to tuck in your tailbone.
Notice how, in this picture, the pelvis area is aiming forward. That is because the tailbone is tucked in. If you don’t tuck in your tailbone, you crunch your lower back and eventually hurt yourself.
If you’re in a lunge, like in the top picture, bend your back knee and tilt your pelvis forward. Then, keep your pelvis secure as you straighten your knee again. You will notice your pelvis will feel more stable.
Next thing is – lift from your upper and middle back. That is where you want to bend from, not your lower back. It’s a little hard to tell in this picture, but the the curve begins above the lower back. The lower back is actually pretty straight in all these backbends.
Also, open your chest. In other words, bring your shoulders back behind you.
Now, if your backbend involves your arms above your head, like in this photograph, don’t forget to draw your shoulders down away from your ears.
Having that said, I wish you the best of luck! One day you may wind up coming around full circle!