I was getting unpredictable crippling sciatica shooting pains down my legs. Simply put, by retraining your posture to minimize spinal curvature your weight is more evenly distributed over cushioning disks reducing tendencies for herniation/bulging which may aggravate nerves. There’s a 2nd edition of the “Eight Steps” book coming out soon so you can probably find a used copy of the current edition for minimal cost. It will give you a basic idea of the method and get you started. I then did a one day group class which, while not cheap, was a good investment for me. I haven’t had a sciatica pain in a few years now.