I used to use one back when I worked at a company that was later sold to Gaiam. I think we got them wholesale or something. I have to say I think my posture was worse and I had MORE back pain sitting on a ball -- I slouched even more than I normally do. My sense is that standing desks are where it's at. Lots of people in my office use them in conjunction with couch breaks.

I've sat on a ball for the past four years and it's the reason I don't have back pain anymore. My back would go out periodically before using the ball.

I'd recommend it to anyone. Get a cheap one at first and try it out. The warning I'd offer are these:

1. Be careful about leaning too hard on your feet and knees. It's easy to move your back slouch into your knees and ankles.
2. The cheap balls will break. Watch out for stuff in your back pockets or stupid people who think it's cool or clever to kick them when you're sitting on them.
3. Do keep them inflated. They leak a little air. You'll get shorter and shorter over the weeks.
4. Go easy on yourself. The first few weeks will make your abdomen hurt. Do half-a-day on the ball and half-a-day in a chair at first.

I've been using one for years, I have an 80cm at home and a 75cm at work. No more stiffness, although I still get sore in my back occasionally, that's usually from sleeping or lifting too heavy.

I used one and looking back, the reason for improving my backpain was that it forced me to sit with better posture.

Once I found the 8 Steps to a Pain Free Back by Gokhale, I have not needed to use the ball because I have improved my posture in sitting, standing, and walking.

I used one at home for a few months, but found myself too fidgety on it: I often rolled around and ended up kind of crouched over it with my chin on my hands/arms on my desk.

Seeing the other comments, I'm thinking now that it might've been too tall for me. If I recall correctly, I couldn't sit with my feet flat on the ground unless I was sitting nearly on the front of the ball.

So perhaps the lesson to learn from my experience is to make sure you get the right size ball. 8)

Not personally, but a friend of mine has used hers at her home PC for some years now as she didn't have a chair. Seems it also helped her backache too :-)

I used one at work a few years ago. Though I don't have back problems to compare its effect to...

My boss used to use one but found it annoying. He recently had a shoulder injury though so its possible that it was somehow exacerbating his injury.

i've been using this balance ball chair for a year now. definitely took some getting used to, but i love it

http://www.amazon.com/Gaiam-Balance-Ball-Chair-Black/dp/B0007VB4NE

65cm for me, I'm short. It's pretty amazing - all stifness and backpain from sitting all day (especially after a workout) has disappeared.

Sitting on an exercise ball is the only thing besides squatting that relieves my pregnancy backaches. I love that thing! Also it's supposed to be good for getting the baby into the correct position for birth.

I've used one for the past 5 months and feel like it has been a good idea. I switched to a standing workstation this week but if that gets tiring I'll go back to the ball. I had no back pain prior to starting, and none while using it either. I do find myself rolling around and fidgeting throughout the day so I know I'm being more "active" than on a conventional chair which is better than doing nothing.

I'm starting to use my exercise ball to sit instead of my chair at home..I don't think I can bring it to work since HR won't allow me (law suit crap etc).

I too have been using the Gaiam ball with rolling base chair. Have to get up every now and then when i notice my posture start to slump, but overall a good way to strengthen the trunk muscles. I've cranked out multiple 12 hour workdays on it.

I tried it but it is a pain in the ass, so to speak. If one does not have to get up frequently then a ball is okay but if one must get up and move about several times in a short time period, a ball is difficult to scoot away from the desk and then get back into position when one sits again.

I had a hunch those gym balls might be good for something.

It is better than a chair, not better than standing. It is also like gambiling- most of the time it will work, and then there is that one time when it blows up and you find yourself on the floor. So I stopped. At first I just got another ball, but once I it happened, it was always on my mind that it could happen again.

I ditched my computer chair a year ago. Moved my computer to a lower desk and exclusively use a balance ball. I have to say, my core/ab muscles are stronger than ever. I've done some other training that has surely helped, but I definitely think constantly sitting on a balance ball whenever I sit has its benefits.