Good posture is fundamentally about alignment. Think of the outline of your body as a set of five perpendicular lines, representing your torso, upper and lower legs, and upper and lower arms. If the lines intersect at right angles, that’s good, and for the most part (except in the “S-curve” your lower back) curves are bad.
Always sit with your hips, knees and ankles at right angles. Keep your head aligned with the midline of your torso, stacked on top of your shoulders. Your lower arms should be perpendicular to your torso on your armrests, and your feet should be flat on the floor.
If you have an ergonomic chair, you can rely on the chair to do the work; adjust the height and depth of your seat pan, then push your torso back until it makes firm contact with the chair back.
There are endless minutiae to good alignment, and everyone’s body is different. But ensuring the planes of your body are aligned, perpendicular and relaxed gets you most of the way there.
Movement
No seated position is healthy if inhabited for too long. You need to get up and move; the Toronto Rehabilitation Institute suggests taking a “movement break” for every thirty minutes that you sit. Here’s a great list of ergonomic stretches to try, but the choice of exercise isn’t as important as getting up and moving.
Set an alarm to remind yourself to take a break every so often, or simply find ways to integrate standing and moving around into your routine; I often take calls standing, walk to get my meals, and fill my water bottle halfway so I have to get up and refill more often.
Environment
Though they aren’t required by any means, the right furniture and accessories can assist you in developing strong ergonomic habits.
In the workstation, an ergonomic chair with points of adjustment for armrests, height, and lumbar is designed to adjust your body into alignment. If you or your team have a larger budget, a standing desk makes it easy to get standing and moving as you work.