This video sums up nicely what I tell every client that I work with. The ideal sitting posture is actually squatting but since people don’t squat in the Western world, the next best thing is to keep your hips/pelvis above your knees.
The reason for this has to do with the mechanics of the pelvis and how it tilts. An explanation that can sound a little complex is made very simple by the visual aids in this clip.
For those interested there are also great resources for foam wedges to keep in the car or at the office to “fix” the sitting surface to a better angle for you. Feel free to call us to discuss your ergonomic needs.