The seated position actually places up to 6x more strain to the low back than standing.
When seated, you can promote better posture by sitting at the edge of the seat, preferably with the knees lower than the hips. I also encourage patients to use a lumbar (low back) pillow to sit as if you were"pooching out" your stomach and sticking your chest out. Also, see my "back pain
/strain" health guide.