Ergonomics 101

Sitting for prolonged periods of time can be a major cause of back pain.

Sitting is a static posture that can cause increased stress in the back, neck, arms and legs, and can add a tremendous amount of pressure to the back muscles and spinal discs. Additionally, sitting in a slouched-over or slouched-down position can overstretch the spinal ligaments and strain the spinal discs.

Besides being uncomfortable, over time poor sitting posture and workplace ergonomics can damage spinal structures and contribute to recurrent episodes of back pain.

Here are some important guidelines to help make sure that your work area is as comfortable as possible and causes the least amount of stress to your spine:

1. Elbow measure:  Begin by sitting comfortably as close as possible to your desk so that your upper arms are parallel to your spine. Rest your hands on your work surface (e.g. desktop, computer keyboard). If your elbows are not at a 90-degree angle, move your chair either up or down.

2. Thigh measure:  Check that you can easily slide your fingers under your thigh at the leading edge of the chair. If it is too tight, you need to prop your feet up with an adjustable footrest. If there is more than a finger width between your thigh and the chair, you need to raise the desk/work surface so that you can raise your chair.

3. Calf measure:  With your buttocks up against the chair back, try to pass your clenched fist between the back of your calf and the front of your chair. If you can’t do that easily, the chair is too deep. You will need to adjust the backrest forward, insert a lumbar support or get a new chair.

4. Lower-back support:  Your buttocks should be pressed against the back of your chair, and there should be a cushion that causes your lower back to arch slightly so that you don’t slump forward as you tire. This support is essential to minimize the load (strain) on your back. Never slump or slouch in your chair, as that places extra stress on your spine and lumbar discs.

5. Eye level:  Close your eyes while sitting comfortably with your head facing forward. Slowly open your eyes. Your gaze should be aimed at the center of your computer screen. If your computer screen is higher or lower than your gaze, you need to either raise or lower it.

6. Armrest:  Adjust the armrest of your chair so that it just slightly lifts your arms at the shoulders. Use of an armrest allows you to take some of the strain off your neck and shoulders, and it should make you less likely to slouch forward in your chair.

While this article is about traditional chairs, some people prefer more active chairs, such as a Swedish kneeling chair or a Swiss exercise ball. Traditional chairs are designed to provide complete support, but a kneeling chair (or Swedish kneeling chair) promotes good posture without a back support, and an exercise ball (or Swiss ball) helps develop your abdominal and back muscles while you sit. It’s advisable to first talk with your doctor prior to using one of these types of chairs if you have an injured back or other health problems.

Finally, no matter how comfortable you are at your desk - prolonged, static posture is not good for your back. Try to remember to stand, stretch and walk for at least a minute or two every half hour. Moving about and stretching on a regular basis throughout the day will help keep your joints, ligaments, muscles and tendons loose, which in turn will help you feel more comfortable, more relaxed and more productive.