Staring at a computer screen for hours at the office every
day can do more than strain your eyes. It can strain your
neck and back and ruin your posture, especially if you're
sitting in an office chair that lacks the comfort and support
you need.
Ergonomics, though certainly not a new word in the world
of office seating, is still as important as ever for good
office posture. Many types of seating actually encourage you
to sit improperly and prevent correct use of your body - and
you may not even realize it.
History and Development
The term "ergonomics" originated from two Greek
words: "ergon," meaning work and "nomoi,"
meaning natural laws. Ergonomists study human capabilities
relative to work demands.
Before ergonomics became a recognized science, an educational
method called the Alexander Technique was developed in the
early 20th century to show people how their everyday habits
of work can be harmful to their bodies. Still used today,
this method teaches people how to avoid work habits that create
excessive amounts of static work by decreasing the amount
of unnecessary muscular force they are applying to their bodies.
In recent years, ergonomists have tried to define postures
that lessen unnecessary static work and reduce the forces
acting on the body. The Alexander Technique has enabled people
to put into practice some basic ergonomic principles, which
have been developed to reduce risk of injury.
Following suit, today's office seating concepts have been
designed to address such principles, which include the following:
1) all work activities should permit the worker to adopt several
different, but equally healthy and safe postures; 2) the largest
appropriate muscle groups available should be used where muscular
force has to be exerted; and 3) work activities should be
performed with the joints, particularly the head, trunk, and
upper limbs at about mid-point of their range of movement.
The Posture Problem
In order to practice basic ergonomic principles, you would
have to be a skilled observer of your own joint and muscle
functioning. Most people are not ergonomic experts; they just
want a comfortable, durable chair that won't ruin their posture.
In order to get the most benefit of ergonomic research, we
must learn how to observe our bodies in a new way, and then
find the chair that best suits us.
If you're not sure whether your office chair is helping or
hindering your posture, ask yourself the following questions:
1) How is your body typically positioned when seated at your
desk?
2) Do you find yourself leaning forward to answer a phone
call or to better focus on your computer screen?
3) Do any particular positions or movements seem to result
in stress or discomfort?
4) Are you acutely aware of areas of tension anywhere in your
body, often called "hot spots"?
5) How often do you rest, stand up, stretch, or change your
line of vision?
With these questions in mind, office furniture designers and
manufacturers themselves have developed a sound philosophy
of what promotes or hinders good office posture, resulting
in office seating that is ergonomically sound.
If, for example, you often find yourself slumping forward
and sitting partly on the end of your spine, you are a victim
of poor office posture. Chronic poor posture can weaken back
muscles; compress the spine and reverse natural alignment
of the lumbar curve; cause back pain and fatigue; and lead
to chronic back problems.
For good office posture, you must learn to sit properly.
You should sit firmly on your pelvic bones with your torso
fully upright, your shoulders back, and your back against
the back of the chair. This positions aids in the development
and support of long-term back health by strengthening back
muscles, maintaining the natural lumbar curve, and helping
to prevent and relieve back pain.
Ergonomics affects more than just your back. In fact, good
office posture is contingent on the proper orientation of
your entire body - from your head to your toes.
Head and Neck
When seated at your desk, the top of your computer screen
should be placed at about 10 degrees below your "straight
ahead" vision, so your head is able to "float"
comfortably above your spine. This allows the back of your
neck to extend, curving slightly up and over. You should be
able to move your head and neck freely and independently without
involving your shoulders.
Ideally, your neck should never feel strained. Staring for
extended periods at the computer screen or any object at a
fixed distance keeps the neck fixed and rigid. To avoid such
tension, place a picture behind your computer screen on the
wall (or pick an object outside the window) so that you frequently
can look at each of the four corners and relax your eyes.
It is also a good idea to stand up and stretch every 20 minutes,
rolling your head in a slow circle in both directions.
Torso and Spine
Your office chair and positioning should allow fluid, effortless
pivoting motions that encourage the gentle bending at the
hip joint, versus the declining, spine-compressing torque
that is common when reaching for a telephone or kneeling over
a file drawer. Some office seats actually force the spine
backward and off-center, which makes fluid bending difficult
and encourages you to slump or overarch your back. It can
actually cut off blood circulation in the legs.
A chair with a firm seat and flat, rigid seatback, such as
Herman Miller's popular "Aeron Chair," encourages
upright, natural positioning of the spine and allows you to
develop your own natural lumbar curve. The chair also offers
"pellicle suspension," which provides support in
all seating postures by distributing body weight equally on
the seat and back.
Kimball, another office furniture manufacturer, also offers
a chair called the "Xtreme," designed to decrease
torso and back rigidity. It comes in high-back and mid-back
models, with contoured support, plus a one-half inch soft
"topper pad" to enhance back comfort and reduce
spinal fatigue.
Shoulders and Arms
Upper and outer shoulder muscles should be kept relaxed when
seated by minimizing the involvement of the deep rotator muscles
in your shoulder. To do this, try to immobilize your whole
arm when typing or writing. Your elbow should move only slightly
when controlling a mouse or writing tool. The computer keyboard
should be placed so that the wrist end of your forearm is
approximately five degrees below parallel to the floor.
The "mix-it" chair, offered by a line of Kimball
office furniture called National, was developed for optimal
ergonomic shoulder and arm support and comfort. The chair
comes with arm adjustments for eight different positions in
height and five different positions in width.
Hands
Good "hand posture" is often overlooked. Your hands
should have a curved, relaxed shape while you type, especially
your pinkies, rather than flat, straightened fingers. The
majority of muscular work should take place on the underside
of your hand. Rather than lifting fingers or turning them
laterally to reach various keys, roll your forearm to move
your whole hand slightly.
You should check to see that muscles on the back of the hand
and between thumb and forefinger remain completely still for
the most part. You should then relax the fingers and the muscles
on the back of your hands momentarily every five to 15 minutes.
Drape your hands palms-down on the top of your legs, and take
a few slow, deep breaths.
Legs and Feet
Finally, the positioning of your legs and feet is critical
to good office posture. Feet should rest comfortably on the
floor, with the soles flat, shoulder-width apart. Ideally,
the seat cushion should be high enough to allow the thighs
to have a slight angle (about five degrees) down from the
hips so that the knees are at least an inch lower than the
hip.
It's important to note that even in following basic ergonomic
principles, different office chairs work better for some than
they do others. What feels comfortable to sit in initially
may not necessarily the best long-term choice for promoting
good office posture. Let an expert help. Remember, you can't
judge a good office chair by the seat of your pants alone.
Author - Beth Bemiss
Office
Chairs - How to Judge 
