If your job or lifestyle requires that you sit for long periods of time, you are at risk for back disorders. And the solutions to avoid back problems may surprise you!

Ergonomics is defined (in plain terms) as fitting the job to the people who have to do it, through the design of equipment and procedures. By applying good ergonomic principals, we can lesson or avoid work related stress, particularly on the spine or extremities. Recent ergonomic studies have changed our "conventional wisdom" about ways to eleviate pain. 

The two greatest problems, for those who sit for long periods of time, are 1) sitting upright or forward, and 2) not changing your position often. The most common assuming is that sitting in a ninety-degree hip position would be the healthiest position. Untrue.

From the perspective of the intervertebral discs it is actually better for us to sit with our hip joints somewhat straightened. And, yes, that position resembles a slouch (what your teachers used to tell you NOT to do). You scoot your rear end forward in the seat. A forward-tilt seat will also support this posture, as do chairs with level seats and reclined backrests. Reclining also lets your back muscles relax. Reclined sitting puts more of your weight against the chair's backrest. This means the discs in your lower back have to hold less weight. Armrests may also help take some of the upper body weight from the discs as well.

Don't sit still for long periods of time. Moving around frequently helps the muscles relax and recover. The movement alternately flexes and unflexes the intervertebral discs-which produces better filtration of fluids into and out of the cores of your discs, keeping them healthier.

To achieve the best long-term comfort you will need to adjust your chair properly. Here are a few tips:

• Seat Height: your feet should be able to rest flat on the floor (not that you should keep your feet flat on the floor, but they should be capable of resting there). Your legs should be free to move into different positions.
• Seat Depth: You should be able to use the backrest of your chair without any pressure behind your knees.
• Lumbar Support: Because every person is shaped differently, you need to have the proper lumbar support height. So, select either a chair with adjustable lumbar support, or a chair that fits your body correctly.

Where you focus your eyes has a large influence on your posture (and, therefore, your back). Your work material should never be too far, too low, or too high to alter your neck position from a comfortable, forward-facing one. Your monitor should be placed at eye level to avoid leaning, twisting, or reaching (like for your mouse, or glancing down or sideways at a document).

Hand positions are also important for proper posture. Keyboard height should be elbow height or lower and wrists should be kept straight. If you feel more comfortable pushing the keyboard back, so that the forearms are supported (assuming the wrist is kept straight). Keep your mouse placement relatively close to the keyboard (next to it if possible).

For an interesting article on office ergonomics, read Convention Wisdom vs. Current Ergonomics.