|
A
group of Scottish and
Canadian medical
researchers used a
new form of
"positional" MRI to
measure spinal angles
and disk height in
twenty-two "healthy"
volunteers to
determine the best
sitting posture for
the back. The
volunteers scanned in
three different
positions: 1)
slouching forward, 2)
sitting upright at 90
degrees, and 3)
reclining backward at
135 degrees. The
researchers looked at
all the data and
concluded that disk
movement and disk
height were most
favorable at the 135
degree sitting angle.
The research group
presented their
findings at the
annual meeting of the
Radiological Society
of North America. The
lead researcher, Dr.
Waseem Bashir of the
Department of
Radiology Imaging at
the University of
Alberta Hospital,
Canada, said "We were
not created to sit
down for long hours,
but somehow modern
life requires the
vast majority of the
global population to
work in a seated
position. This made
our search for the
optimal sitting
position all the more
important."
Science Daily Link on this
research
BBC News Link on this
research
COMMENTS:
I agree that we were not
created to sit for
uninterrupted periods of
time and that finding the
optimal sitting position is
important. That's about all
I agree with concerning
this study. Unfortunately I
do not have a copy of the
entire study, but I think
enough can be ascertained
from the news releases to
make a few constructive
comments:
1. Reclining backward at a
135 degree seat angle
obviously distributes the
weight of the upper body
over a larger area (more
body weight into the
backrest) and thus is less
stressful on the lower
spine. The same would apply
to a 140, 145, or 150
degree angle. In fact, it
would be far better for
your spine to simply lie
down flat at 180 degrees
and not sit up at
all.
2.
Reclining backward at
a 135 degree seat
angle may be "the
best biomechanical
sitting position" for
the back as claimed
by the research, but
it isn't for the
neck. A person
sitting at a 135
degree seat angle
must counter-recline
their head and neck
forward at a 45
degree angle to look
straight ahead as one
is required to do
when working in a
seated position. Dr.
Bashir said "Sitting
in a sound anatomic
position is
essential, since the
strain put on the
spine and its
associated ligaments
over time can lead to
pain, deformity and
chronic illness." I
think pain, deformity
and chronic illness
is exactly what
you'll get in your
upper back and neck
if you sit reclining
backward at a 135
degree seat
angle.
3. The
thoracic spine
(ribcage) must be
upright for the head
and neck to properly
positioned over the
body. This is
accomplished by
supporting the normal
lumbar arch
(lordosis) in the
lower back and
placing your weight
into your seatback.
Apparently the
researchers did not
perform a positional
MRI on volunteers
seated in this
supported manner.
Sitting upright at 90
degrees with a proper
lumbar support and
your weight into the
seatback is the
optimal sitting
position for the
whole spine,
including the back
and neck.
Nevertheless, a
person must get up
and move about
periodically because
the body requires
motion (circulation,
digestion,
respiration) for good
health.
4.
Radiologists (the
researchers in this
study) are
specialists.
Specialists tend to
focus on specific
parts and sometimes
forget to consider
the holistic
viewpoint. Here the
back is the focus of
study and the
recommendations made
to help the back will
result in harm to the
neck. Let's try to
remember that people
(presumably even the
study volunteers)
have backs and necks,
and all those parts
are affected by
sitting position.
Good posture will
always incorporate
neutral alignment of
the head, ribcage,
pelvis and lower
extremity, from front
to back and from side
to side. That is
elementary.
5. The only reasonable way
to achieve a 135 degree
angle between the thighs
and the trunk is to sit
straight from the waist up,
but in a chair that allows
the pelvis to tilt slightly
forward at the top. In this
position, the lower back
arch is maintained, and the
thighs can angle downward -
as a person would sit up
correctly from the waist
down on a barstool or
riding a
horse.
|
