Office Ergonomics

Office Ergonomics: Effects And Advances in Recent Research

The Chair: Conventional wisdom is that the chair should be at a height that allows the feet to reach the floor when the legs are in the “conventional wisdom” position of 90 degrees (at the knee). The ninety – degree knee posture is not “correct “ergonomics although it is not a harmful position. The legs should move very often, not stay fixed in ninety degree position. The chair should, if possible, be low – low enough for the feet to rest on the floor, even when extended. However, if the chair is at a good height but the keyboard height can’t be adjusted to elbow height or lower, then it’s necessary to adjust the chair upwards. In this case, a footrest is an option.

Placement of the mouse: Closer is usually better – next to the keyboard is the goal.

Footrests: Footrests are a distinctly second – class choice because the feet only have one place to be, and leg postures are limited. However, if the chair is already low enough, footrests offer a chance to change leg postures and are recommended.

Upright posture, with the hips at ninety degrees: A great deal of research supports the idea of a much wider hip angle – with one hundred thirty degrees or so as an “optimum” angle. The reasoning here is that when the hips are straightened, the vertebrae of the lower spine are aligned with each other in a way that reduces and evens out pressure on the inter vertebral discs. Further, sitting upright is less desirable than reclining. When reclining, the lower back muscles work less and the spine supports less weight, since body weight is held up by the chair’s backrest.

Keyboard height: Conventional wisdom is that this should be at elbow height. This is wrong, or at least too narrow. Variation from elbow height is fine, especially in the lower – than – elbow direction.

Keyboard angle: The keyboard angle depends entirely on the forearm angle, and should be in the same plane as the forearm. So, a low keyboard should be slanted back. Some people expect they won’t be able to see the keys if the keyboard is sloped back, but this is usually not a problem.

Position of wrists: These should be kept upright.

Monitor height: The current recommendation is that eye height is the highest a monitor should be, not the best height. Many people find a low monitor to be more comfortable for the eyes and neck. The best solution in most cases is to put the monitor on the work surface, and not on the top of the C.P.U.

Wrist rests:  Conventional wisdom about wrist is that they can do no wrong and should always be used. This is wrong. They may be able to cause harm if they’re too thick, too thin, too hard, or have sharp edges (even sharp edges of foam). They also can cause harm if they’re constantly used – they probably should be used just during pauses. The carpal tunnel is under the wrist / palm and should not be subjected to much pressure. Conventional practice is to supply wrist rests for the keyboard but not the mouse. Mouse wrist rests are a good idea in many cases, but the same warnings apply.

Rest breaks: Research supports the idea of very short breaks done very short breaks done very frequently – for example, 30 second breaks every ten minutes or so. These should happen in addition to the normal fifteen – minute coffee breaks.

Computer and peripheral arrangement: Conventional wisdom for computer and peripheral arrangement is for the keyboard and monitor to be aligned directly in front of the user, and for note pads and documents to be placed to the side. This is wrong for all those computer users who spend more time reading / writing and tracking the document. For these users it makes more sense for the papers to be centre in front of you and for the keyboard to be angled off to the side. Arrange your tools and equipment so that those items used most frequently are placed for easy access.

Correct posture: Finally, conventional wisdom holds that there is such a thing as a “correct” posture. In reality, posture change seems to be as important as posture correctness, especially with regard to the intervertebral discs in the spine. These discs lose fluid over the course of the day because of the weight they carry. It appears that posture change is essential to help pump fluid back into the discs. People who stand all day tend to have back problems – but so do people sit still all day.

It is therefore important to appreciate the need for good workstation ergonomics and the need for the need for the adaption of best practice when working at a computer workstation. This will ensure that problems associated with poor working arrangements including musculoskeletal disorders and localized pains are reduced as much as possible, thereby enabling the worker to be productive for longer periods of time.


by Mr. Omondi(Engineering Workshops, JKUAT)