Desk Sitting Positions
There is not just one
correct position for sitting at a desk. There is really a whole spectrum of
satisfactory positions and obviously in the course of a day’s work variation
will help reduce fatigue.
It is perfectly possible to sit completely upright with the body
in the same shape as it is in standing, but supported under the seat bones and
not by the legs via the hip joint. This will obviously use exactly those
muscles that are used in standing and must be a good way of sitting for
deskwork as the body is really just standing from the seat bones. I refer to
this as Alexander sitting as this is exactly what is taught as part of the
Alexander Technique.
Note that this is much easier if the thigh is angled
down from the hip to knee and becomes impossible if the knee is significantly
above the hip.
Most people however will
choose to use a backrest and this must support the pelvis. If you wish to sit
very vertically it would still help to have the seat angled downwards from hip
to knee. Obviously, the extra force from the back rest will tend to make you
slide down the seat. There is therefore a happy mean to be looked for between
the seat angle and amount of pelvic support. Alternatively, the seat can be
returned to the horizontal and the backrest reclined slightly to maintain the
open angle between the trunk and thighs. If the eyes are to face directly
forwards to a monitor for instance when the body is slightly reclined there
must be some flexion in the spine or neck and this is best achieved by
spreading it over a much of the spine as possible i.e. let the middle part of
the back bend where lumbar support normally stops it bending.
The body does not have
to be kept strictly in the standing shape if we are writing at a desk with the
eyes pointed towards the paper. The whole spine can be evenly curved without
harm.
This sort of position
can be taken further back by lowering the seat, tilting the seat back slightly,
reclining the back rest more and allowing more bend in the mid back so that the
head is still facing forwards.
Or Even more!
This position is still a
perfectly satisfactory working position so long as the backrest incorporates
pelvic support. The seat used for all these demonstrations is the Pelvic Posture 20-25 Universal Task
Chair.
Note that the work that needs to be done in the
upper back muscles is a maximum in the most upright position, even if the
pelvic support is good, and is much reduced in the more reclined position.
Looking to the future, it is perfectly logical to argue that the more reclined
position reduces the muscular effort in the upper back. If so, an even more
reclined position, with a really effective head rest would go one step further
and reduce the muscular effort in the neck. (Note that holding the heavy head
stationary during a day’s work with very little movement is exactly what
muscles were never designed to do).
The last stage in the spectrum of sitting
positions is what many of us tend to do at least some of the
time..........particularly when so much work can be done just with the
"mouse hand" and a microphone. Although universally
condemned there is actually nothing wrong with this position. It is the
slouched position with the pelvis balanced on the gluteal muscles, the spine
evenly curved up to the shoulder blades, which is the next point of support,
and the top of the chair back being used as a headrest underneath the occiput
at the base of the skull. |
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