Pros and Cons of Ergonomic Office Equipment |
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Pros and Cons of Ergonomic Office Equipment
All "ergonomic" items have some drawbacks or possibilities for misuse. This section explains some of the possibilities for office accessories and furniture. Although this page has to do with stuff you can buy, keep in mind that many ergonomic problems can be fixed by rearrangement, adjustment or modification of existing items. In this page: "Purpose" means what the gizmo is supposed to correct. You may not need to correct whatever it is the gizmo's for, so you may not need to buy one. "Misuse and Drawbacks" talks about how the gizmo can actually do harm, potentially. Everything can do harm, so this section is important. "General End-User Instructions" speaks to the person who's going to use the gizmo. It talks about adjusting it and work habits. The "Instructions" section, or something like it, should be given IN WRITING to every recipient of that particular gizmo. Always. "Choices" describes some of the options available out there in the marketplace --- some of the variations offered by various vendors. The main point of the "Choices" section is to get you to look beyond the one or two examples of a gizmo you have seen. There may be fancier and better versions. This is a very long web page (about a dozen mortal pages). Here are shortcuts: To allow a better viewing arrangement by
moving the person back from the screen or worksurface For
some keyboard trays, there is only enough room for a keyboard, forcing a long reach to use
a mouse Keyboard trays can be adjusted too low, too high, or at the wrong angle, causing bent
wrists The
angle of the tray/keyboard is as important as its height. Adjust the tray so the keyboard
is approximately at the same angle as your forearm; for a low keyboard this may mean
tilting the keyboard slightly backward. If mice are consistently used, the tray should hold the mouse as
well as the keyboard. Angle adjustability will allow more precise matching of the keyboard angle to the
forearm angle. Backward angles may be preferred by some users. The tray should feel stable. The tray or mechanism should not interfere with the knees or posture. Most of the
lever- type controls can be adjusted to change the lever angle. This is usually done by
pressing a button on the top of the lever. A wrist rest should be available but may not be necessary. Some trays have special installation requirements, such as a minimum worksurface
depths. A few can be installed in right-angle corner workstations. There is nothing sacred about keyboard trays. An alternative is to place both the mouse
and keyboard directly on the worksurface and adjust the worksurface to an appropriate
height. To take some weight off the
shoulders and reduce shoulder muscle work To soften the surface under the wrist Some individuals may become dependent on wrist rests and
may bend their wrists to reach side or bottom keys rather than move their forearms Wrist rests with sharp edges, even foam ones, may be uncomfortable Wrist rests of any design may cause pressure inside the carpal tunnel in some people A wrist rest is usually placed immediately
in front of the keyboard or mouse. However, the position is up to you --- some people push
the keyboard back and use the wrist rest under their forearms. Some people's wrists are sensitive to pressure underneath them. Others are sensitive to
pressure underneath the palm. Find a spot that is comfortable for you. Wrist rests for keyboard should be used mainly during pauses. While keying, use the
rest lightly, and move your whole hand to reach side keys rather than bending your wrist
sideways. The rest should be deep enough (front to back) to spread
the load out over a large area. Less than about two inches is considered too narrow. Wrist rests should not have sharp edges in contact with the skin. Material should be cleanable or the rest should be cheap enough to be discarded when
soiled. Breathable material is more comfortable in warm or humid environments. Material should not have too much friction; should not constrain the arms. Rests do not necessarily have to be soft if contours and size distribute pressure well.
Anti-static features are useful if properly grounded, and if static has been a
demonstrated problem. Wrist rests for mice should move (slide, roll) with the mouse. Many
people who use a mouse heavily prefer to rest their whole forearm while
mousing. This is
fine, but be careful of resting the elbow and the funnybone nerve on anything hard or
sharp. Also, when mousing, try to sometimes move the mouse with the whole forearm, keeping the
wrist straight. At other times, keep the forearm still and move at the wrist. The point is
to not overdo any one method. An alternative to mouse trays is to place both the mouse and
keyboard directly on the worksurface and adjust the worksurface to an appropriate height. To prevent the wrist from dropping (bending back) during keyboard or mouse
work To avoid pressure under the wrist or elbow that may occur with wrist rests or chair
armrests Lack of
up-down or tilt motion in current models feels constraining to some users Far more expensive than wrist rests Avoid resting the elbow itself on the forearm rest, because the
funnybone nerve that runs through and around the elbow is sensitive to pressure. Forearm rests should allow plenty of movement. They should not immobilize the forearm
so the wrist is doing more sideways bending than before. Most current forearm supports are articulating "arms"
that attach either to the front of the worksurface or chair armrests. Another design involves fixed, padded extensions from the worksurface. Some people use wrist rests as forearm rests. This can be functional and appropriate. To
reduce awkward postures of the arms or hands during keying or mouse. The main target
postures are deviation (sideways bending at the wrist) or pronation (working with palms
facing the floor). Often, a wrist rest
needs to be reshapes to fit an unusual horizontal or vertical angle of the keyboard.
Inexpensive raw-foam wrist rests are a good solution because they can be cut. Some alternative devices use thumb motions frequently and can tire the thumb or cause
tendinitis. Some alternative keyboards need additional arm support, because the keyboard requires
higher hand positions than usual. There is no evidence (yet) that trackballs, etc. are healthier or unhealthier than
mice. The main problem is overuse regardless of the kind of device. The best approach may
be to switch back and forth frequently from one kind of pointing device to another. For
Macs, this is easy because Macs support several devices without having to plug/unplug.
Newer PCs with the Universal Serial Bus (USB) can do the same thing. For
pointing devices (mice, trackballs, styluses, touch pads), consider switching back and
forth between different kinds of devices, rather than completely replacing one device with
another. Keyboards that adjust from a closed position allow users to use the
board in the usual way, or to gradually adapt to new positions. For mice, choices include trackballs, mouse pens, mice that use one finger, and touch
tablets, plus a wide variety of mouse shapes and sizes. When choosing alternatives,
evaluate whether the alternatives truly use different muscles. Having a variety of keyboards and pointing devices available to users often produces
the best results. To allow users to alternately key and write on the same
surface without slumping or hunching their shoulders To reduce back problems by allowing users to alternate standing and sitting during the
day Getting a worksurface at the
best height for you is more difficult than it sounds. There may be three different
"right" heights: the right height for your forearms and shoulders (no pushing up
of shoulders), the right height for your eyes and head (putting the work at a good viewing
distance that avoids slumping), and the right heights for your legs (allowing you to sit
the way you like, which may including crossing your legs). The right height for you may be very different from the right height for another person
who is as tall as you. A lot depends on whether you are long-waisted, nearsighted,
short-armed, and so forth. Maintenance adjustability is usually acceptable for people who do the same
task most of the time. Multiple users at the same workstation should have user
adjustability rather than maintenance adjustability. (Options include from crank,
electrical, or counterbalanced mechanisms.). Especially for multiple operators, tables that display the height setting make it easy to find a favorite setting. Worksurface edges can be important to comfort for people who read or write frequently (Edges can be rounded, sloped, or cushioned) Sloping the worksurface may be desirable, especially for people who read and write a lot or, sometimes, people who prefer to work reclining. To allow forward- back or sometimes up-down movement of the monitor to accompany posture changes or fit different users To store keyboards when not in use Many people find a low monitor height to be most comfortable in the long run, so the monitor arm usually should be kept in its lowest position. However, there is no right or wrong. Some people are uncomfortable with low monitors. If you are experimenting with monitor height because of neck or shoulder discomfort, try a number of different positions for a day or two each, and keep track of how your upper back feels. If you wear bifocals or trifocals, your monitor probably should be much lower than usual. Ask your eye doctor about "computer glasses," which may give you more freedom to sit in different positions. The size of the tray and weight capacity should be matched to the monitor. Friction vs. crank vs. spring- counterbalanced height mechanisms affect usability if the individual(s) needs to frequently adjust height. Spring-counterbalanced, if well adjusted, is the easiest to use. Different means of attachment (worksurface clamp, grommet, floor) should be matched to the situation. Glare screens DO NOT reduce the magnetic fields that are currently (and controversially) of concern. No glare screen does this, despite misleading claims. Know the appropriate cleaning procedures and keep the screen clean. Glare screens can only do so much. Reducing light sources around you may be necessary. If a window is causing screen glare, consider changing the location of the monitor. If your monitor is right in front of a window, you may not be experiencing glare but you may get eyestrain from having too much contrast in your field of vision. Grounded screens can reduce static electricity (dust buildup). Many people confuse static electricity with controversial magnetic fields. Jargon in ads (H-field, E-field, VLF/ELF, etc.) helps perpetuate the incorrect idea that magnetic fields can be reduced by these products. To avoid neck twisting by bringing the document close to the monitor and keeping it at a readable angle To reduce eyestrain by keeping the document at approximately the same distance and angle as the screen If most of your work involves looking at paper rather than at the screen, consider putting the paper in front of you, rather than the monitor. For these jobs, a document stand is essential. Documents should be illuminated enough to be easily readable, but too much light on documents can result in a strong contrast between the brightnesses of the screen and the document. This kind of contrast can cause eyestrain. Task lights with dimmers or multi-way switches allow individual adjustment Lights should evenly diffuse light over an appropriate area and should not shine into users' eyes. Footrests should not cause the foot to rest on sharp or hard edges. Big footrests give more choice of leg posture. Footrests should be stable enough to stay in place but mobile enough to be moved when by the feet when needed. Footrests that allow exercise or massage the feet may be beneficial. To avoid back pain by supporting multiple postures and/or "good" postures; to reduce muscle effort required in sitting
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