Now let's get to the knitty gritty! Just to let you know - I receive no benefits whatsoever from letting you know about this ball. It has helped me through some "tight" spots (muscles that is) in releasing overworked, stressed out muscles. The ball is a Gymnic Heavymed Gr2000. I've seen it online for $20 - to nearly $100 on different sites. Gymnic also produces smaller and larger sizes than the one on my video - the smaller they are the more they will dig into your back - the bigger they are the gentler they will be on your back. I use the yellow (2,000kg/4.4 lb) size since it perfectly opens the muscles in my back.
Now, a little more detail on how to use it! Simply get into the position of doing situps. Place the ball on the floor and lay your mid-back on it. Lift your bottom up off the ground, feet still planted on the floor, and roll up and down your spine slowly. If you need to steady yourself on the ball, do this next to a sofa and use it to guide you up and down your back. If you have a certain part of your back that's stressed, you can lay your back on the spot and relax into it. It's best to wear stretchy form fitting clothing and long hair should be tied up so it doesn't get caught under the ball.
To open your shoulders, get into situp position, place ball in the middle of your back between shoulder blades - but a little to the left on the edge of your left blade. Lift your right hip up and roll on the ball horizontally toward your left arm. Do this over the entire shoulder blade from the top to the bottom moving laterally from the middle of your back over your shoulder blade toward your arm. Then do the other side with the left hip on the ground and right hip lifted up.
This simple technique can bring peace to your muscles and ease to your mind.
If you have any back injuries or other back issues other than run-of-the-mill muscle aches, please consult a physician before you take on any exercise or restorative methods such as this.