It is probably the simplest instructable but the most effective one.
Background : I've had multiple back injuries from either slipping or just doing nothing. It is one of those things that you are damned with. I have spent $1000s of dollars on physio, massage, thumper, acupuncture, tennis balls, massage chairs and computer chairs, etc. They all work in their own little way but I always wanted something I can keep with me in the car or on the boat or in my computer bag just in case I got in to a situation that I would need a quick massage/circulation in my lower back and relieve the pain. Most pain killers don't work on me. If you don't have acute back pain, you are one of the lucky ones but I'm sure you know someone who does and I can guarantee you that if you give them this instructable, you will be the best friend they have ever had so please pass it along. My intent is to share with others who are in the same pain I am in, nothing else.
I'm not a chiropractor or have had any back specific training so like all the other instructables, use at own risk.
Racquet ball - balls - I used 3 for this instructable
sock - 1
rubber band - 1
Look at the photos. Stuff the 3 racquettball, balls in the sock and tie a rubber band around it. You can now put it on a chair and place it where you want to apply a massage or relieve the pressure. IT WORKS beautifully. Keep one near your bedside table when you cant get out of bed, or in your car etc.
The most effective way to use it is to put the balls right where you have a "knot" and let gravity work on your body. Move the balls around if you don't feel slight pressure. Keep them for a minute or 2. Do this a few times till your knot is released.
Hope this helps. Please vote if you like this instructable