ESSENTIAL
ERGONOMICS for PREVENTION and PRODUCTIVITY
2. Body Position
A
static seated posture for long periods of
typing is one of the main causes of muscle and
joint strain, especially in the upper and lower
back. Altering your seated position
periodically can be extremely beneficial in reducing
fatigue and strain. See more details here.
Important
points for body posture while working:
Back
- lumbar support:
the curve in the lower part of your back (lumbar curve)
is one of the most important structural elements of a
good overall posture. With a good lumbar curve,
your pelvis will be positioned in a forward tilt, and
your center of gravity will move forward, putting most
of your weight over the pelvis instead of onto the
spine. The value of a good
pelvis and lower back position cannot be
over-emphasized! Everything you ever read about
good seated position will talk about the need for a
lumbar support. The lumbar support must be at the
correct height. See diagram. Try to
use a chair with a built in lumbar support.
Otherwise, use other options such as a rolled up towel,
foam roll or one of the many commercially available,
reasonably priced, chair add-on pieces. See recommended products.
Upper
arms at side of body:
your upper arms should be right next to your body, not
angled forward as in 'reaching' for the keyboard.
With your arms comfortably at your sides, and elbows
resting on arm rests, your hands should naturally reach
the keyboard without any forced reaching.
Forearms
parallel to floor:
the keyboard should be at the correct height. This
means that if your chair and table are the correct
height, your elbows will be at 90 degrees and your
forearms will be parallel to the floor. With this
position, you are not reaching 'upward' to a keyboard
that is too high, which could result in straining of the
shoulder and upper back muscles.
Elbows
resting on arm rests:
If possible, use a chair with arms rests that are high
enough for you to rest your elbows on, to take the
weight of your arms. This is most important if you
spend much of each day typing on the keyboard.
Elbow
90 degrees:
With your hands on the keyboard and wrists or palms
resting on a wrist or palm rest, your elbows should be
at 90 degrees.
Wrists
straight:
Looking at your wrists from the top and from the side,
there should be no angles (flexing or extending).
Your wrists should be in a 'neutral'
position.
Fingers
slightly flexed (curled) to reach each key:
Each finger should be bent or flexed just enough to
gently rest on the home row keys. Most of the
movement for typing should happen at the small finger
joints, with your hand and arm as stable as possible,
with as little movement as possible.
Seated
position: It's a good idea to alter the way you sit to shift
your center of gravity and weight bearing to reduce strain placed
on specific joints.
Two suggestions for positions
are: Posture 1: Thighs parallel to floor,
hips
and knees 90 degrees,
lumbar support on chair, feet
flat on floor Posture 2: Wedge on chair to angle body forward, thus moving center
of gravity forward and altering posture.
Alternate between these two
positions if possible. Achieving the forward tilt of your
body is possible simply by using a foam wedge, or one of the many
reasonably priced chair add on pieces