Sort of agree. I do Pilates and yoga 3-5x a week, as well as regular body weight training and surf, so am fairly fit and very focused on back and core health.

Sort of agree. I do Pilates and yoga 3-5x a week, as well as regular body weight training and surf, so am fairly fit and very focused on back and core health. For me, it's the lack of movement during intense periods of focus - four hour blocks, over many years, sometimes 16 hr days. At least with the bad chair, I'm always moving, keeping the support muscles active. When I sit for a long time, and forget the core, I think is when compromise to key systems occur. What I'm not good at is getting up every 20 min, if I did, I'm sure I'd be fine.