Sitting

Consider a standing desk, sitting is bad for you.

Sit for twenty minutes, stand for ten minutes, walk; repeat.

Find reasons to walk more.

Consider a treadmill at your standing desk.

If you must sit choose a chair that provides support for your lower back, sit straight.

Adjust your work surface height and your chair to assume a comfortable and natural body posture.Sit square try not to lean to one side, it is bad to cross your legs at the level of your knee.

Try to maintain an angle of 110 degrees between your trunk and thigh when sitting, keep your knees below your hips.

Get up often even for short breaks.

To promote comfortable leg postures, consider the following:

Clear away items from beneath your desk to allow comfortable leg positions and movement.
Use a footrest if your feet do not rest comfortably on the floor.

To minimize reaching and to promote comfortable shoulder and arm postures, consider the following:

Place your keyboard and mouse or trackball at the same height; these should be at about elbow level. Your upper arms should fall relaxed at your sides.
When typing, center your keyboard in front of you with your mouse or trackball located close to it.
Place frequently used items comfortably within arm's reach.
Get up often even for short breaks.