Computer WorkStation Ergonomics Equipment
Chairs | Keyboard Trays | Keyboards | Monitors/Monitor Arms | Glare Screens | Pointing Devices (Mice) | Work Stations | Document Holders | Foot Rests | Disability Issues | Laptop Ergonomics | Headsets
Chairs
A chair that is well-designed and appropriately adjusted is an essential element of a safe and productive computer workstation. A good chair provides necessary support to the back, legs, buttocks, and arms, while reducing exposures to awkward postures, contact stress, and forceful exertions.
Increased adjustability ensures a better fit for the user, provides adequate support in a variety of sitting postures, and allows variability of sitting positions throughout the workday. This is particularly important if the chair has multiple users.
To learn more about ergonomic chairs please refer to the following links:
- Ergonomic chair operating instructions
- National Institutes of Health (NIOSH) chair description
- Centers for Disease Control and Prevention (CDC) ergonomic chair information
An adjustable keyboard tray is a tool that facilitates the placement of the computer keyboard and mouse so that the equipment can be used with hands wrists and elbows in a comfortable neutral position. Ideally, an adjustable keyboard should allow adjustments to the height and tilt of the keyboard and it should not interfere with non- computer related tasks when not in use. Finding an appropriate keyboard for a workstation will depend on many factors including the existing equipment configuration, the frequency and duration of use, the number of users, etc. Some keyboard trays are sold in two pieces, an adjustable arm and a platform.
Many ergonomic problems associated with computer workstations occur in the shoulder, elbow, forearm, wrist, and hand. Continuous work on the computer may expose soft tissues in these areas to repetition, awkward postures, and forceful exertions, especially if the workstation is not set up properly.
The following adjustments should be made to your workstation to help prevent the development of an ergonomic problem in the upper extremities:
- First adjust your chair (see ergonomic chairs), then with your arms resting comfortably at your side, raise your forearms to form a 90 degree angle with your upper arms.
- Adjust keyboard height so shoulders can relax and allow arms to rest at sides. An articulating keyboard tray is often necessary to accommodate proper height and distance.
- Position the keyboard directly in front and be close to the user to avoid excessive extended reaching.
- Forearms parallel to the floor (approximately 90 degree angle at elbow).
- Mouse should be placed adjacent to keyboard and at the same height as the keyboard. Avoid extended and elevated reaching for keyboard and mouse. The back of the wrist should be kept flat (in a neutral position). Do not rest the hand on the mouse when you are not using it. Rest hands in your lap when not entering data.
- A padded wrist rest will help to keep your wrist in a straight and neutral position while typing and keep your arms off the sharp edges of the work surface.
- Do not rest your wrists or hands on a palm or wrist rest when you are keying. These rests are designed to provide support only during breaks from keying.
- The slope of the keyboard may need to be adjusted so that it is flat in order that your wrists are straight, and not bent back while you are typing.
- Press the keys gently; do not bang them or hold them down for long periods. Keep your shoulders, arms, hands, and fingers relaxed.
For more information on keyboards and keyboard trays please see the following links:
Keyboards
To date, there is little information to assist people interested in purchasing alternative keyboards. The scientific evidence about whether alternative keyboards prevent musculoskeletal disorders is inconclusive at this time. The NIOSH Guide on Alternative Keyboards provides basic information about common alternative keyboard designs and their effects on work posture.
Adjustable Flat LCD Monitors
Flat panel LCD monitors offer many advantages over CRT monitors. In general, they are lighter, take up much less desk space and are easier to adjust. They also use far less power and can represent a cost saving over time.
Another approach would be to buy a monitor that has an adjustable stand. In most cases these stands will not provide as much flexibility as a monitor arm. Some monitors appear to have height adjustability, some can be swiveled and turned and some can do both.
The computer monitor should be placed so the top of the screen is at or just below eye level when seated in an upright position. The following suggestions can help prevent the development of eye strain, neck pain and shoulder fatigue while using your computer workstation:
- Make sure the surface of the viewing screen is clean.
- Adjust brightness and contrast to optimum comfort.
- Position the monitor directly in front of the user to avoid excessive twisting of the neck.
- User must position the monitor at a comfortable viewing distance, approximately 18-30 inches from the user.
- Position monitors at right angles from windows to reduce glare. Close window blinds as needed to reduce glare from sunlight.
- Position monitors away from direct lighting which creates excessive glare or use a glare filter over the monitor to reduce glare.
- Adjust the monitor tilt so that ceiling lights do not reflect on your screen.
- If a document holder is used, it should be placed at approximately the same height as the monitor and at the same distance from the eyes to prevent frequent eye shifts between the monitor screen and reference materials.
- Get regular eye check-ups.
- Adjust as needed for larger screens. You may need to sit farther away and increase the font size to take full advantage of the larger screen.
Bifocal and trifocal wearers have to pay particular attention to the placement of their monitor. Wearers of bifocals and trifocals often unknowingly tilt their heads backwards so they can read the screen through the lower portion of their glasses. This can sometimes lead to neck, shoulder, and back discomfort. Potential solutions include either lowering the computer monitor or purchasing glasses designed specifically for working at the computer.
For more information on monitors and monitor arms please view the following links:
Appropriately placing lighting and selecting the right level of illumination can enhance your ability to see monitor images. For example, if lighting is excessive or causes glare on the monitor screen, you may develop eyestrain or headaches, and may have to work in awkward postures to view the screen.
Potential Hazard:
- Direct light sources (for example, windows, overhead lights) that cause reflected light to show up on the monitor make images more difficult to see, resulting in eyestrain and fatigue.
Possible Solutions:
- Place the face of the display screen at right angles to windows and light sources. Position task lighting (for example, a desk lamp) so that light does not reflect on the screen.
- Clean the monitor frequently. A layer of dust can contribute to glare.
- Use blinds or drapes on windows to help reduce glare. Note: vertical blinds work best for East/West facing window and horizontal blinds for North/South facing windows.
- Use glare filters that attach directly to the surface of the monitor to reduce glare. Glare filters, when used, should not significantly decrease screen visibility. Install louvers or “egg crates”, in overhead lights to re-direct lighting.
- Use barriers or light diffusers on fixtures to reduce glare from overhead lighting.
If your position requires frequent telephone use, you may want to consider using a telephone headset. Cradling the phone between your head and neck can cause severe neck pain. The use of a telephone headset allows the user’s hands to be free while working without cradling the telephone on the shoulder.
You may want to consider using a headset if you; have a position where you frequently use the telephone and/or have extended conversations, if you cradle the phone on your shoulder while talking, the phone can not be located within your reach.
Pointing devices such as a mouse now come in many sizes, shapes, and configurations. In addition to the conventional mouse, there are trackballs, touch pads, finger tip joysticks, and pucks, to name a few. Selection and placement of a pointer/mouse is an important factor in creating a safe computer workstation.
- The mouse is present in virtually every office environment. Handed versions of mouses are designed specifically to the contours of either the right or left hand.
- Placing the mouse, trackball, or other input device too far away, too low, or too much on one side can cause shoulder, wrist, elbow, and forearm discomfort. Placing the input device directly in your immediate reach zone offers natural comfort and maximum hand-to-eye coordination.
- Do not bend your wrist upward. Make sure you are sitting high enough for the workstation to be slightly below elbow height so that your hand rests naturally on the mouse.
- Mousing demands a certain level of surface stability; if used on a keyboard tray, the tray should not wobble or tip.
- A trackball has an exposed ball that you manipulate with your fingers. It requires the use of different muscle and tendon groups than does a mouse, and can add variety to your manipulation of computer information. Some trackball designs, however, may cause discomfort and possible injury to the area around your thumb, which stretches and reaches to maneuver the trackball.
- Test different models of mousing devices, trackball or other input devices. Consider the shape and size of the devices, how comfortably it fits into your hand, ease of operation, and any special features that might make your job easier.
In addition to the mouse and trackball, a variety of other input devices are available. Consider your task requirements and physical limitations.
- Touch pads allow you to move the cursor on the computer screen by simply gliding your finger across a small pad. Unlike mouses, trackballs, and other pointing devices, touch pads have no moving parts to clog or breaks, so they never require disassembly for cleaning.
- Touch screens allow you to point directly at an object. They require little or no training, are faster than other pointing devices, and require no extra work surface. However, the disadvantages of touch screens include arm fatigue, smudges, optical interference, and increased glare.
- Voice input allows you to "talk" to your computer. Currently, such programs can understand and respond to natural speech delivered at rates of up to 160 words per minute.
- Pen-like devices use pressure, light, electromagnetic disruption, or radio frequencies to enter and manipulate information through contact with the computer screen or a horizontal pad. A pen pad requires about as much room on the work surface as does a mouse. If pen technology is used on a horizontal pad, a workstation must provide adequate non-glare lighting for both it and the computer screen.
For additional information on mice please view the following link:
A non-adjustable desk may be difficult to set up properly as a computer workstation in some instances. An alternative may be a simple single or two level table that can be height adjusted. In most cases, a simple unit that can be adjusted to fit the current occupant when it is assembled may be adequate. More complex electrical and mechanical systems that provide very easy and quick adjustability are available if needed. This may be useful when multiple users use the same workstation or if the workstation needs to accommodate various tasks.
Standard furniture cannot accommodate everyone’s needs. A taller person may need a one-time adjustment to have his or her work surface raised somewhat; a shorter person may need a footrest or other accessories. Adjustable furniture may be needed in situations where people share or use the same workstation.
- The desktop should be organized so that frequently used objects are close to the user to avoid excessive extended reaching.
- The work surface should have a matte finish to minimize glare or reflections.
- The area underneath the desk should always be clean/uncluttered to accommodate the user’s legs and allow for stretching.
- If a fixed-height desk is used, add a keyboard tray that adjusts vertically to provide added adjustability.
- A footrest should be used if, after adjusting the height of the chair, feet do not rest flat on the floor.
- Use a headset or speaker phone to avoid neck and shoulder discomfort if you use a phone frequently throughout the day.
- Place the phone on the side of your non-dominant hand (i.e., left side if right-handed, right side if left-handed).
- Position your desk lamp (if you use one) so that it illuminates source documents without causing either glare on the computer screen or direct illumination to your eyes.
- A document holder should be used if documents are referred to during keying. The document holder should:
- Be stable and adjustable (height, position, distance, and angle of view).
- Support your document on either side of or below the monitor.
- Be at the same distance from your eyes as the display screen to avoid frequent changes of focus and you should be able you to look from one to the other without moving your neck or back.
For more information on computer workstation please view the following link:
Document holders keep printed materials needed during computer tasks close to the user and the monitor. Proper positioning of document holders depends on the task performed and the type of document being used. Appropriate placement of the holder may reduce or eliminate risk factors such as awkward head and neck postures, fatigue, headaches, and eye strain.
Documents should be at the same height and distance as the monitor.
Potential Hazard:
Documents positioned too far from the monitor may require awkward head postures or frequent movements of the head and neck to look from the monitor to a document. Those awkward postures can lead to muscle fatigue and discomfort of the head, neck, and shoulders.
Potential Solutions:
- Document holders should
- Allow you to place documents at or about the same height and distance as the monitor screen and
- Be stable when loaded with heavier documents such as a textbook
- A document holder can be positioned directly beneath the monitor. This provides a sturdy writing surface, if written entries are necessary, and reduces frequent movement of the head, neck, or back.
- Task lighting on the document should not cause glare on the monitor.
Foot rests are recommended to relieve pressure on the lower back and thighs when chair height and depth may not adequately accommodate this. Although to some degree, a foot rest is a matter of individual preference, look for a foot rest that adjusts to different heights and that also may provide some movement to allow easy change of positions. It should be of a size and weight that interferes minimally with the users ability to move around. Footrests are generally inexpensive.
What to do if you are Injured:
Fill out an accident report and inform your supervisor. Schedule an appointment with your health care provider. Follow any instructions given by the Disability Claims Unit (DCU). Additional Resource: Disability Compliance Office 495-1859
The use of laptop computers poses an ergonomic challenge – Laptops do not easily allow basic ergonomic adjustments since they have a fixed design. When the keyboard is in the proper position for the wrist, the screen is not at an adequate height for viewing and vice versa. Using a laptop, however mobile and convenient is a tradeoff between poor neck/head posture and poor hand/wrist posture.
To alleviate this potential problem we recommend the use of a laptop stand. Laptop stands come in different sizes, styles, shapes and colors.
How to use the laptop stand:
- Angle the laptop screen so that you can see the screen with the least amount of neck strain. Position the screen so that the top line of the screen is at or below eye level. The laptop screen should be placed between 20 – 40 inches away from the eye.
- USE A SEPARATE KEYBOARD and MOUSE. Such as the devices used on a standard desktop computer.
Tips for Safe Use of Laptop Computing
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Transporting the Computer
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Chairs | Keyboard and Keyboard Trays | Monitors/Monitor Arms | Glare Screens | Pointing Devices (Mice) | Work Stations | Document Holders | Foot Rests | Disability Issues | Laptop Ergonomics
