The chair "tilts" your seat and lifts your feet off the ground. It makes for an odd tilt to your spine. It is not ergonomically correct and it is very uncomfortable after about 1/2 hour of sitting in it.
This chair is comfortable and it is so much better on my back and neck than the expensive chair that i had previously! If you have neck and back issues - this is a great chair!
This is a great office chair. I spend a minimum of eight hours per day in it and it's comfortable throughout the day. The only drawback I've experienced with it is that the cushion for the lumbar support doesn't stay locked so I have to readjust it regularly throughout the day. If not for that I would have given it a five star rating.