Set up your computer desk correctly and practice good computer posture.
Suggestions for computer workstation ergonomics. Setting up your office using ergonomic considerations is important to protect your health. Most ergonomic experts agree on certain ergonomic designs that will further your well being and productivity. However, every computer workstation and its user is different, and if you have problems implementing some of the following recommendations you should seek professional advice.
Ergonomic design and correct computer posture are essential for good computer workstation ergonomics. Learn how to maintain good posture at an ergonomic workstation and there's a good chance you'll computer-related injury. The following recommendations have been adapted from CUErgo, Professor Alan Hedge, and other ergonomic sources.
Ergonomic computer furniture and accessories from onestopergonomics.com assist you in creating a more healthy and comfortable workstation. Adjustable LCD monitor arms, ergonomic keyboard trays, arm rests and wrist rests allow healthy positioning. Height and tilt adjustable computer workstations and laptop stands that can be used in sit stand position are worthwhile investments for your health and productivity.
How will the computer be used - Do you require an ergonomic design for one user/Multiple user - hours/day?
- How many users? If the computer will only be used by one person then the arrangement can be optimized for that person's size and shape, and features such as a pneumatic adjustable desk may not be necessary. If this computer is going to be used by several people, you will need to create an arrangement that most closely satisfies the needs of the extremes, that is the smallest and tallest, thinnest and broadest persons, as well as those in between.
- How long will people be using the computer? If it's a few minutes a day then ergonomic issues may not be a high priority. If someone will be using it for more than 1 hour per day, it is advisable that you create an ergonomic arrangement. If it's more than 4 hours, then you should immediately implement a thorough ergonomic setting.
What kind of computer workstation ergonomics will be used for desk top or laptop computer?
- Desktops? - Most ergonomic design guidelines for computer workstation arrangements assume that you will be using a desktop system where the computer monitor is separate from the keyboard. These allow you to easily place each of the separate components (monitor, keyboard, mouse) at comfortable settings.
- Laptop? Otherwise known as notebook computers, these portable computers have enjoyed tremendous growth in sales and computing capability. They are designed for short periods of computer work, but many people are using them for full time computing. Ergonomic design Guidelines for laptop use are more difficult because laptop design is inherently problematic. That's because when the screen is at a comfortable height and distance, the keyboard isn't and vice versa. If you will be using a laptop for sustained lengths of time, you should consider purchasing:
- An external keyboard, preferably with a negative-tilt keyboard tray.
- This will let you arrange your workspace to create a good workstation layout. See "Tips for Using A Laptop Computer."
What furniture will you use - work surface, keyboard tray?
- Make sure that the computer system (monitor, CPU system unit, keyboard, mouse) is placed on a stable working surface with adequate room for proper arrangement. If this work surface is going to be used by an adult for writing on paper as well as computer use, the work surface should be between 27"- 30" above the floor (suitable for most adults). Ideally, a height adjustable workstation offers personalized setting.
You should consider attaching a keyboard/mouse tray system to your work surface. Choose a system that is height adjustable, that allows you to tilt the keyboard down away from you slightly (negative tilt) for better wrist posture. This allows you to use the mouse with your upper arms relaxed and as close to the body as possible, and with your wrist in a comfortable and neutral position.
What chair will be used?
Choose a comfortable chair for the user to sit in. It should be comfortable to sit on, have a good backrest that provides lumbar support, and also offer a means to adjust both the height and the tilt of the backrest. Studies show that the best seated posture is a reclined posture of 100-110 degrees NOT the upright 90 degree posture that is often portrayed. When the user sets the chair's backrest to the recommended reclined posture the chair starts to work for the body and there are significant decreases in postural muscle activity and intervertebral disc pressure in the lumbar spine. Erect sitting is not relaxed, but sustainable, reclined sitting is.
What kind of work will the computer be used for- what software?
- Word processing - arranging the best keyboard/mouse position is high priority.
- Surfing the net, graphic design - arranging the best mouse position is high priority.
- Data entry- arranging the best numeric keypad/keyboard is a high priority.
Games - arranging the best keyboard/mouse/game pad is a high priority.
What can you see - documents, monitor screen positioning?
Make sure that any paper documents that you are reading are placed as close to the computer monitor as possible and that these are at a similar angle - use a document holder where possible. The computer monitor should be placed:
- Directly in front of you and facing you. It should not be angled to the left or right. This helps to eliminate excessive neck twisting. Also, whatever the user is working with, encourage him/her to use the screen scroll bars to ensure that what is being viewed most is in the center of the monitor rather than at the top or bottom of the screen.
- Center the monitor on the user. The body and/or neck should not be twisted when looking at the screen. However, if you are working with a large monitor and spend most of your time working with word processing software such as MS Word, which defaults to creating left aligned new pages, and you don't want to have to drag these to more central locations, try aligning yourself to a point about 1/3rd of the distance across the monitor from the left side.
- Monitor height - Users should not have to tilt heads up or down to view the screen image clearly. When you are seated comfortably, a user's eyes should at least be in line with a point on the screen about 2-3" below the top of the monitor casing (not the screen). This 2" to 3" guideline is a starting point from which you can make minor adjustments for your individual viewing comfort. Sit back in your chair at an angle of around 100-110 degrees (i.e. slight recline) and hold your right arm out horizontally, your middle finger should almost touch the center of the screen. Research shows the center of the monitor should be about 17-18 degrees below horizontal for optimal viewing, and this is where it will be if you follow the simple arm extension/finger pointing tip. You actually see more visual field below the horizon than above this (look down a corridor and you'll see more of the floor than the ceiling), so at this position the user should comfortably be able to see more of the screen. If the monitor is too low, you will crane their neck forwards, if it's too high you'll tilt their head backwards and end up with neck/shoulder pain.
- Bifocals and progressive lens - Sometimes individuals who wear bifocals or progressive lenses find they need to set their computer monitor height slightly lower than the recommended height. Slight adjustment may be fine, but even if you wear bifocals or progressive lens, proper sitting position can compensate. Postural problems with bifocals can occur if you sits erect or even hunched forwards. So, if you sit back in your chair in a reclined posture (with you back at around 110 degrees) and if you slightly tilt the monitor backwards and place this at a comfortable height you should be able to see the screen without tilting your head back or craning your neck forwards. The problem with low monitors is that they cause neck flexion and suffer more from glare.
- Viewing distance - The monitor should be at a comfortable horizontal distance for viewing, which usually is around an arms length (sit back in your chair and raise your arm and your fingers should touch the screen). At this distance you should be able to see the viewing area of the monitor without making head movements. If text looks too small then either use a larger font or magnify the screen image in the software rather than sitting closer to the monitor. More recent studies have found that having the monitor set at a greater distance than the arms length guideline is perfectly fine for many people, as long as the screen image can be clearly seen and read without strain or poor posture adjustment.
- Screen quality - Use a good quality computer screen. Make sure that the text characters on your screen look sharp, and that they are a comfortable size (you can change the screen resolution to find a comfortable and clear character size). If you have a CRT monitor and notice a screen flicker (LCDs don't flicker) out of the corner of your eye, you should try increasing the refresh rate of your monitor (with a CRT PC you can change monitor resolution and refresh rates using the Monitor Control Panel in your Settings folder; Macs use the Monitor Control Panel). You can also consider replacing your CRT with an LCD display.
- Eye checkup - There are natural changes in vision that occur and also vision changes that result from eye strain. It's a good idea to periodically have your eyes checked by a qualified professional.
If any screen adjustments feel uncomfortable then change them until the arrangement feels more comfortable or seek further professional help
Ensure good computer posture as well as ergonomic design!
Good posture is the basis of good workstation ergonomics and the best way to avoid a computer-related injury. Employers, teachers and parents can help ensure good posture by committing and being attentive to proper computer ergonomics:
Watch the user's posture! Make sure that...
- the user can reach the keyboard keys with their wrists as flat as possible (not bent up or down) and straight (not bent left or right).
- the user's elbow angle (the angle between the inner surface of the upper arm and the forearm) is at or greater than 90 degrees to avoid nerve compression at the elbow.
- the upper arm and elbow are as close to the body and as relaxed as possible for mouse use - avoid overreaching. Also make sure that the wrist is as straight as possible when the mouse is being used.
- the user sits back in the chair and has good back support. Also check that the feet can be placed flat on the floor or on a footrest.
- the head and neck are as straight as possible .
- the posture feels relaxed and comfortable for the user.
Keep frequently used items close!
- Make sure that those things the user uses most frequently are placed closest to the user so that they can be conveniently and comfortably reached without excessive outreach or strain. This includes the phone, document holders, stapler, or other items, depending on the job requirements of the position.
- Center the alphanumeric keyboard. Make sure that the user is centered on the . Most modern keyboards are asymmetrical in design (the alphanumeric keyboard is to the left and a numeric keypad to the right). If the outer edges of the keyboard are used as landmarks for centering the keyboard and monitor, the users hands will be deviated because the alphanumeric keys will be to the left of the user's midline. Move the keyboard so that the center of the alphanumeric keys (the B key, is centered on the mid-line of the user).
A good ergonomic workstation arrangement:
Computer user work best in a neutral, relaxed, ideal typing posture that will minimize the risk of developing any injury. An ideal keyboard arrangement is to place this on a height adjustable negative-tilt tray or an a manually adjustable height desk. An ideal mouse arrangement is for this to be on a flat surface that's 1-2" above the keyboard and moveable over the numeric keypad. If you want a surface at the level of the keyboard base then make sure that this can also be angled downwards slightly to help to keep your hands in wrist neutral while you are mousing, and keep your elbow is as close to the body as possible while you work.
Where will the computer be used - lightning, ventilation, noise
- Lighting - Maintain even lighting that is not excessively bright. You shouldn't see any bright light glare on the computer screen. If you do you can either move the monitor screen's placement, lower the light level, or use a good quality, anti-glare screen. Ideally, position your desk and monitor at right angle to the window. Do not set your monitor so that it's backed to a bright window or facing a bright window, which will cause the screen to "wash out." You can use a shade or drapes to control window brightness.
- Ventilation - Make sure that you use your computer somewhere that has adequate fresh-air ventilation and where there is adequate heating or cooling so that you feel comfortable when you're working.
- Noise - Excessive or specific noises can cause stress for individuals. This can lead to muscle tension and can increase the risk of injury. Try to choose a quiet place for your workstation, and use low volume music to mask the hum of any fans or other sound sources.
Take frequent breaks - Practice the following:
- Eye breaks - Looking at a computer screen for lengths of time can cause some changes in how the eyes work, cause you to blink less often which means your eyes receive less lubrication, and also exposes more of the eye surface to the air. It is recommended that users briefly look away from the screen to a more distant object every 15 minutes. This allows the muscles inside the eye to relax. Also, blink your eyes rapidly for a few seconds. This refreshes the tear film and clears dust from the eye surface.
- Micro-breaks - During a micro-break (< 2minutes) you can briefly stretch, stand up, move around, or do a different work task e.g. walk to get a drink of water, etc). Take one every 30 to 60 minutes. Also, because most typing is done in bursts rather than continuously, between these bursts of activity you should rest your hands in a relaxed, flat, straight posture.
- Exercise breaks - Perform a minute or two of gentle stretching and exercises to help relieve muscle fatigue. You should do these every 1-2 hours.
- Ergonomic software - Working at a computer can be hypnotic, so that often you don't realize how long you've been typing and mousing. There are several software programs available that will monitor your computer use and prompt you to take rest breaks and exercise at specific intervals.
What about ergonomic gizmos?
These days just about everything is labeled as being "ergonomically designed" and much of the time this isn't true and these so-called ergonomic products can aggravate a situation. If you're thinking about buying an "ergonomic product" ask yourself the following four questions:
Does the product design and the manufacturer's claims make sense?
What research evidence can the manufacturer provide to support their claims? Be suspicious of products that haven't been studied by researchers.
Does it feel comfortable to use the product after an initial "getting acquainted period? Some ergonomic products may feel odd or slightly uncomfortable at first because they often produce a change in your posture that's beneficial in the long-term. If a product continues to feel uncomfortable after a reasonable trial period (at least a week) time then stop using it.
What do ergonomics experts say about the product? If they don't recommend it don't use it.
Functional computer-related "ergonomic" products:
- "Ergonomic" keyboards - Most of these are keyboards where the alphanumeric keys are split at an angle. For a non-touch typist, this design can be a disaster! The split design only addresses issues of hand ulnar deviation, and research studies show that vertical hand posture (wrist extension) is more important. There is no consistent research evidence proving that most of the split-keyboard designs currently available really produce any substantial postural benefits. For most people, a regular keyboard design works just fine if it's placed in the proper neutral position.
- "Ergonomically" designed mouse - Many of these mouse designs or alternative input device designs can work well to improve your hand/wrist posture. However, it's important to ensure that you can use these at your workstation with your upper arm relaxed and as close to your body as possible. Overreaching to an "ergonomic mouse" defeats any benefits of this design.
- Wrist rests - These were extremely popular a few years ago, but research studies haven't demonstrated substantial benefits for wrist rests in most situations. They do offer protection compared to having your wrist resting on a sharp desk edge which can impact nerves in the wrist. The pads can also compensate for improper desk height settings. wrists. When not used properly, these pads can actually increase pressure inside the carpal tunnel by compressing the under surface of the wrist (look at your wrist and you'll probably see blood vessels, and these shouldn't be compressed!). If you choose to use a wrist rest, it's recommended you select one from a quality manufacturer that has a broad, flat, firm surface. Also, rest the heel of your palm, not your wrist, on this. Don't rest your wrist on its surface while typing, but only in-between typing periods.
- Support braces/gloves - There is no consistent research evidence that wearing wrist supports during computer use actually helps reduce the risk of injury. If you do like wearing a wrist support, make sure that it keeps your hand flat and straight, not bent upwards. There are documented cases in which workers who wore wrist braces due to computer work pain did not receive relief until Cornell University researchers customized the ergonomic setting of the employee's desk. (There is some evidence that wearing wrist supports at night in bed can help relieve symptoms for those with carpal tunnel syndrome.
Sit-stand workstations - The use of a height adjustable work surface for sitting and standing work is becoming fashionable. However, there is scant evidence that sit-stand furniture has cost effective benefits. The evidence suggests that there may be a reduction in back discomfort, but the research for this has not used adequate comparison groups (e.g. testing people who stand for the same time at the same frequency without doing keyboard/mouse work). There is no evidence that sit-stand improves wrist posture when keying or mousing. Logically, the real benefit of sit-stand is just that, changing between sitting and standing. But standing in a static posture is even more tiring than sitting in a static posture, so movement is important. We recommend that the most cost effective way to obtain the benefits from sitting and standing is for people to sit in a neutral work posture and then intermittently to stand and move around doing other things, like filing papers, making phone calls, getting coffee, making photocopies etc.) rather than trying to keyboard or use a mouse while standing. On the other hand, there are work sites and specific work responsibilities that may benefit or require a sit-stand computer work surface for reasons other than ergonomics.
- Height adjustable, split work surfaces - With respect to wrist posture, the issues are the same for height adjustable, split work surfaces and sit-stand work surfaces:
- If the surface is too low the hand will be in greater extension
- If the surface is too high the elbow will be in sustained flexion
- If it's a flat surface, a strong argument can be made to incorporate a negative-slope keyboard tray arrangement.
A flat computer desk surface can not be set at an appropriate height for the five main tasks of office work:- keyboarding, mousing, viewing the screen, viewing documents, and writing. These all require different heights for an optimal arrangement. A negative-slope keyboard tray system serves as the height and angle adjustment mechanism for the keyboard, and the mouse platform serves as the height and angle adjustment for the mouse when attached to a work surface that is set for writing height. There are a number of new split work surface designs that may work quite well to achieve optimal monitor positioning.