Chairs with seatback contribute to back pain

Until recently, only the wealthy people had a chair with a seatback. Human beings used to either sat on the ground or on stools or benches.

A seatback makes sitting more passive than just sitting on a bench or stool because you use fewer muscles to stabilize your upper body. If you don't use your muscles in your body, they atrophy. And weak muscles make us more prone to pain.