I am always trying to work on my posture because I spend a big chunk of my day sitting or at a desk. I have thought about a bosu ball chair, but I have also read some negative reviews on what it does to the back. I may use the balance ball just for sitting on around the house.
Good posture does wonders for the body, makes you seem more confident, and flattens the abs. Plus, if you strengthen the abs in the process, that can help prevent back injury and keep you standing tall throughout your life.
I found this video on YouTube that has been pretty effective so far. All you have to do is lay on your back! Easy. *Note: These are posture exercises and use your back which may be a sensitive area for some, so make sure to ask your doctor before you begin a new exercise program.
I used 1 or 2 towels first, and then I tried the foam roller. The towels work best. I may get a noodle and cut that in half and see if that is more effective.
And these 2 videos have been helpful as well:
Yoga, pilates, and general strength training can benefit posture greatly as well!