Work the whole core

According to a recent blog post in the NY Times by Gretchen Reynolds the latest research indicates that to stabilize the spine you should be working all the core muscles not just the deep abdominal muscle. You can read the blog here. Based on my experience this has certainly helped me and the P90X program had a lot to do with that. The overall P90X program, not just Ab Ripper X, works your entire core and you can feel the posture improve with almost every workout. I have turned the corner with my long standing back issues (maybe I should blog a bit about my experience with back problems) and I attribute a lot of that to strengthening my core, from the upper legs to just below the chest.