Seeing as that design is never mentioned in respects to ergonomics and certainly wouldn't "bounce" anything, I strongly suspect the quoted passage was referring to the inflated balls you sit on.
You're right. That's one of the disadvantages of linking to the printer friendly version of an article. You miss out on those "link" things that made this "interweb" thing famous:
I'm just going to continue as usual, using the ball chair and alternating with a normal chair if needed. My spine feels great and definitely has a more natural shape when sitting on the ball vs. a normal chair.
http://images.businessweek.com/mz/10/19/0509_chairs.pdf
I'm just going to continue as usual, using the ball chair and alternating with a normal chair if needed. My spine feels great and definitely has a more natural shape when sitting on the ball vs. a normal chair.