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12 tips for an Ergonomic Computer
Workstation
1. Use a good chair with a dynamic chair back and sit back
2. Top of monitor casing 2-3" (5-8 cm) above eye level
3. No glare on screen, use an optical glass anti-glare filter
where needed
4. Sit at arms length from monitor
5.
Feet on floor or stable footrest
6. Use a document holder, preferably in-line with the computer
screen
7. Wrists flat and straight in relation to forearms to use
keyboard/mouse/input device
8. Arms and elbows relaxed close to body
9. Center monitor and keyboard in front of you
10. Use a negative tilt keyboard tray with an upper mouse
platform or downward tiltable platform adjacent to keyboard
11. Use a stable work surface and stable (no bounce) keyboard
tray
12. Take frequent short breaks (microbreaks)
Read more about setting up your workstation.
Creating a good ergonomic working arrangement is important
to protecting your health. The following 10 steps are a brief
summary of those things that most Ergonomists agree are important.
If you follow the 10 steps they should help you to improve
your working arrangement. However, every situation is different,
and if you can't seem to get your arrangement to feel right
or you are confused about some of the following recommendations
you should seek professional advice.
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| 10
steps for a good ergonomic workstation arrangement |
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Work through the following 10 steps to help you decide on
what will be a good ergonomic design for your situation:
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How will the computer be used? |
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- Who will be using the computer?
- 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 an adjustable
height chair may be unnecessary. If it's 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 these extremes.
- 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 it's 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 an ergonomic arrangement.
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| 2) |
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What kind of computer will be used? |
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- Desktops - most ergonomic guidelines
for computer workstation arrangements assume that
you will be using a desktop system
where the computer screen is separate from the keyboard.
- Laptop computers are growing in
popularity and are great for short periods of computer
work. Guidelines for laptop use are more difficult
because laptop design inherently is problematic -
when the screen is at a comfortable height and distance
the keyboard isn't and vice versa. For sustained use
you should consider purchasing either:
- an external monitor
- an external keyboard, preferably with a negative-tilt
keyboard tray
- both, and
- a docking station
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and then arranging your workspace to create a good workstation
layout. See
"5 tips for using a Laptop Computer".
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| 3) |
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What furniture will you use? |
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- Make sure that the computer (monitor,
CPU system unit, keyboard, mouse) are placed on a
stable working surface (nothing that wobbles) with
adequate room for proper arrangement. If this work
surface is going to be used for writing on paper as
well as computer use a flat surface that is between
28"-30" above the floor (suitable for most
adults). 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 for
better wrist posture (negative
tilt), and that 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.
Thinking about a sit-stand
workstation,
see below.
Thinking about a height-adjustable
split workstation,
see below.
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| 4) |
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What chair will be used? |
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- Choose a comfortable chair for the user to sit in.
If only one person is using this the chair can even
be at a fixed height providing that it is comfortable
to sit on and has a good backrest that provides lumbar
support. If more than one person will be
using the computer, consider buying and a chair with
several ergonomic
features. 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. In the
recommended posture the chair starts to work for the
body and there are significant decreases in postural
muscle activity and in intervertebral disc pressure
in the lumbar spine. Erect sitting is NOT relaxed,
sustainable sitting, reclined sitting is.
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What kind of work will the computer be used
for? |
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Try to anticipate what type of software
will be used most often. |
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- 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.
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| 6) |
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What can you see? |
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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: |
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- Directly in front of you and facing you,
not angled to the left or right. This helps
to eliminate too much 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
so that the body and/or neck aren’t twisted
when looking at the screen. However, if you are working
with a large monitor and spend most of your time working
with software like MSWord, 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.
- Put the monitor at a comfortable height
that doesn't make the user tilt their head up to see
it or bend their neck down to see it. When you are
seated comfortably, a user's eyes should be in line
with a point on the screen about 2-3" below the
top of the monitor casing (not the screen). 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. From that starting position
you can then make minor changes to screen height and
angle to suit. 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 -
even if you wear bifocals or progressive lens, if
you sit back in your chair in a reclined posture (with
you back at around 110 degrees) that is recommended
for good low back health, rather than sitting erect
at 90 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. Postural
problems with bifocals can occur if you sit erect
or even hunched forwards. The problem with low monitors
is that they cause neck flexion and suffer more from
glare. Recent studies have shown that the best position
for a computer monitor is for the center of the screen
to be at around 17.5 degrees below eye level. Try
to align your eyes with the top of the viewing area
of the screen, and this should put the center about
right geometrically.
- 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.
- 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 can
see the screen flickering out of the corner of your
eye you should try increasing the refresh rate of
your monitor (with a PC you can change monitor resolution
and refresh rates using the Monitor control panel
in your Settings folder, with a Mac you can use the
Monitor control panel). You can also consider using
a good quality glass anti-glare filter or an LCD display
(like a laptop screen).
- Eye checkup - there are natural
changes in vision that occur in most people during
their early 40's. 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.
- Use a document holder that can
be comfortably seem:
- use an in-line document holder
that sits between the keyboard/keyboard tray and
screen and is aligned with your body midline so
that all you have to do is look down to see the
documents and raise your eyes to see the screen.
- use a screen-mounted document
holder and position this to the side of your screen
that is your dominant eye
- use a freestanding document holder and position
this next to the side of the screen and slightly
angle it so that it follows a curve from the side
of the screen.
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| 7) |
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Posture, posture posture! |
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Good posture is the basis of good workstation
ergonomics. Good posture is the best way to avoid a computer-related
injury. To ensure good user posture: |
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- 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).
- Make sure that 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.
- Make sure that 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.
- Make sure 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.
- Make sure the head and neck are as straight as
possible.
- Make sure the posture feels relaxed for the user.
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| 8) |
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Keep it close! |
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- 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.
- Make sure that the user is centered on the alphanumeric
keyboard. 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 user’s 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).
- Make sure that the phone is also close to you if
you frequently use it.
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| 9) |
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A good workstation ergonomic arrangement |
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will allow any computer user to work 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. 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.
Check
out the 10 tips for using a computer mouse. |
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Where will the computer be used? |
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Think about the following environmental
conditions where the computer will be used: |
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- Lighting - make sure that the lighting
isn't too bright. You shouldn't see any bright light
glare on the computer screen. If you do, move the
screen, lower the light level, use a good quality,
glass anti-glare screen. Also make sure that the computer
monitor screen isn't backed to a bright window or
facing a bright window so that there's the screen
looks washed out (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 that has adequate heating or cooling
so that you feel comfortable when you're working.
- Noise - noise can cause stress
and that tenses your muscles which can increase injury
risks. Try to choose a quiet place for your workstation,
and use low volume music, preferably light classical,
to mask the hum of any fans or other sound sources.
- Take a break!All Ergonomists
agree that it's a good idea to take frequent, brief
rest breaks: Practice the following:
- Eye breaks - looking at a computer
screen for a while causes some changes in how
the eyes work, causes you to blink less often,
and exposes more of the eye surface to the air.
Every 15 minutes you should briefly look away
from the screen for a minute or two to a more
distant scene, preferably something more that
20 feet away. This lets the muscles inside the
eye relax. Also, blink your eyes rapidly for a
few seconds. This refreshes the tear film and
clears dust from the eye surface.
- Micro-breaks - 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. During
a micro-break (< 2 minutes) you can briefly
stretch, stand up, move around, or do a different
work task e.g. make a phone call). A micro-break
isn't necessarily a break from work, but it's
a break from the use of a particular set of muscles
that's doing most of the work (e.g. the finger
flexors if you're doing a lot of typing).
- Rest breaks - every 30 to 60
minutes you should take a brief rest break. During
this break stand up, move around and do something
else. Go and get a drink of water, soda, tea,
coffee or whatever. This allows you to rest and
exercise different muscles and you'll feel less
tired.
- Exercise breaks - there are
many stretching and gentle exercises that you
can do to help relieve muscle fatigue. You should
do these every 1-2 hours.
- Ergonomic software - working
at a computer can be hypnotic, and often you don't
realize how long you've been working and how much
you've been typing and mousing. You can get excellent
ergonomic software that you can install on your
computer (free download available at http://www.magnitude.com).
The best software will run in the background and
it will monitor how much you've been using the
computer. It will prompt you to take a rest break
at appropriate intervals, and it will suggest
simple exercises.
- 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 make
things worse. If you're thinking about buying an
"ergonomic product" as yourself the following
4 questions:
- Do 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
for a long period? Some ergonomic products may
feel strange or slightly uncomfortable at first
because they often produce a change in your posture
that's beneficial in the long-term. Think of some
products as being like new shoes that initially
may feel strange but then feel comfortable after
being used for a while. If a product continues
to feel uncomfortable after a reasonable trail
period (say 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.
There are many computer-related "ergonomic"
products, the most common ones being:
- "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
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 put in the proper
neutral position.
- "Ergonomic" mice
- many of these mouse designs or alternative
input device designs can work well to improve
your hand/wrist posture. However, it's important
to check that you can use these with your upper
arm relaxed and as close to your body as possible.
Overreaching to an "ergonomic mouse"
defeats any benefits of this design. Check
out the 10 tips for using a computer mouse.
- Wrist rests - these were
very popular a few years ago, but research studies
haven't demonstrated any substantial benefits
for wrist rests. In fact, a wrist rest can actually
increase pressure inside the carpal tunnel by
compressing the undersurface of the wrist (take
a look at your wrist and you'll probably see
blood vessels that shouldn't be compressed!).
Studies by Dr.
David Rempel at the University of Berkeley,
California, show that pressure applied to the
underside of the carpal tunnel is transferred
into the tunnel itself via the transverse carpal
ligament and that intracarpal pressure doubles
with a wrist rest compared with floating the
hands over a keyboard. If you choose to use
a wrist rest, using one with a broad, flat,
firm surface design works best, and rest the
heel of your palm on this NOT your wrist. Try
not to rest while you're actually typing, but
rest in between bursts of typing mo vements.
Avoid soft and squishy wrist rests because these
will contour to your wrist, restrict the freedom
of movement of your hands, and encourage
more lateral deviation during typing. Look at
the surface of a typical wrist rest that's been
used and you'll see that it gets eroded away,
which means that the user has been sliding their
wrists over the surface which also compresses
the blood vessels often visible at the wrist.
Remember, your hands should be able to glide
above the surface of a wrist rest during typing,
don't lock them in place on the rest while you
type.
- 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 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 worksurface 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 in termittently 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.
Recent research suggests that electronic sit-stand
workstations, that can be quickly adjusted,
allow each worker to modify the height of their
worksurface throughout the day, and this may
reduce musculoskeletal discomfort and improve
work performance.
- Height adjustable, split worksurfaces-
with respect to wrist posture, the issues are
the same for height adjustable, split worksurfaces
and sit-stand worksurfaces:
- 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 then it's just the
same argument as is used above for a negative-slope
keyboard tray arrangement.
- You can't set a flat worksurface
at an appropriate height for the 5 main tasks
of office work - keyboarding, mousing, writing,
viewing documents and viewing the screen- 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 worksurface that is set for
writing height. Monitor height is best adjusted
by a separate monitor pedestal rather than trying
to move a whole worksurface. There are a number
of new split worksurface designs that may work
quite well to achieve optimal monitor positioning.
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