All of us -- not just children -- should follow simple guidelines in how to sit properly behind a desk. For children, there are several factors to consider when setting up a desk environment. Select the chair carefully. The child’s back should be fully supported by the chair; when the child sits, there should be a 90-degree angle between the back and the upper legs. The chair seat should not compress behind the knees: the seat should not be too long, and the lower legs should be able to pivot freely at the knees. The feet must be able to rest firmly on the floor (or, for very small children, on a support that sits above the floor level). The entire foot should be in contact with the floor, both toes and heels.

Ergonomics Guidelines for Children

The popliteal angle -- the angle between the upper and lower parts of the leg, pivoting at the knees -- should be greater than 90 degrees; i.e., the lower legs should not routinely pivot back toward the body. The upper arms should be close to the body and relaxed, hanging from the shoulders, not flexed forward. The elbow angle should be greater than 90 degrees, and the wrists neutral, with the wrist and hand level with the forearm.

In order to achieve this ergonomic posture, be sure to select furniture that’s proper for your child’s build. Take you child shopping with you; have him or her sit at various desk and chair configurations, with a keyboard on the desk, to ensure that he or she can sit properly. Of course, as your child grows, you may need to replace furniture accordingly; or, if you start out with a desk that’s a bit too high, be sure to purchase a footrest so the feet don’t dangle.

The “seat pan” -- the horizontal part of the chair -- should be appropriately sized, allowing for at least an inch of clearance outside each hip. The height should be adjustable, to allow for fine tuning; if different children of different heights will be using the same chair, make sure it can be adjusted to fit all users. The chair should provide adequate lumbar support for the lower back. Additionally, the chair back should extend to the middle and upper backs as well, providing good support up and down. Make sure that the seat pan is made of quality material; some low-density foams will not keep their shape, eventually causing discomfort and fatigue. The chair should recline easily, allowing for back movement; it should have a five-pedestal base with casters that allow the chair to glide along the floor. And it should swivel.

Other than the chair, help your child organize his or her workspace so that it is ergonomic as well. The “normal work area” can be defined as the space that is easily reached by your child, sitting comfortably in the chair without having to bend or twist the body in a rigorous way. If your child types from a book or document, then purchase a document holder that sits upright on the desk and position it as close to the screen as possible. This prevents your child from twisting the neck, or leaning forward too often to read a document that’s lying flat on the desk. And the computer screen should be centered as well; your child should not have to look up or down, tilting the neck backward or forward, for comfortable viewing. You can easily change the angle of the screen so your child’s neck does not have to tilt.

The work surface itself -- the desk -- should be stable. Make sure that the computer keyboard and mouse are properly sized for your child’s hands; if the child’s hands are small, then consider purchasing a smaller keyboard. The keyboard should be tilted toward the child, not level with the work surface.

And more, make sure the screen is glare-free, and that the natural light coming into your child’s work space does not create glare on any documents or other items on the desk. If there’s

glare, your child will have to shift position and tilt his or her head, perhaps in uncomfortable or incorrect ways.