RESEARCH - An aching back? Well, don't sit up straight!

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An aching back? Well don't sit up straight!

Medical Studies/Trials

Published: Tuesday, 28-Nov-2006

By using a new form of magnetic resonance imaging (MRI),

ish and Canadian researchers have been able to show that sitting in an

upright position places unnecessary strain on the back.

Sitting in this posture for hours at a time can lead to chronic

back pain say the researchers.

Lead author Dr. Waseem Amir Bashir, of the Department of

Radiology and Diagnostic Imaging at the University of Alberta Hospital,

Canada says " 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 " .

The researchers say the best position in which to sit at your

desk is leaning slightly back, at about 135 degrees.

Back pain is the most common cause of work-related disability in

much of the developed world and is a leading cause of job-related

absenteeism.

The study was conducted at Woodend Hospital in Aberdeen,

Scotland, and by using a positional MRI machine, the team were able to scan

the backs of twenty two volunteers with healthy backs as the patients moved

sitting positions during the test.

Traditional scanners have required patients to lie flat, which

may mask causes of pain that stem from different movements or postures.

Dr. Bashir says a 135-degree body-thigh sitting posture was seen

to be the best biomechanical sitting position, as opposed to a 90-degree

posture, which most people consider normal.

Back pain is the most common cause of work-related disability in

much of the developed world and is a leading cause of job-related

absenteeism.

Dr. Bashir and colleagues hope that by identifying bad seating

postures and allowing people to take preventative measures to protect the

spine, back strain will be reduced and fewer work days will be lost.

Dr. Bashir says man was not created to sit down for long hours,

but somehow modern life requires the vast majority of the global population

to do so and the search for the best sitting position was all the more

important.

The patients were asked to adopt three different sitting

positions: a slouching position, in which the body is hunched forward (e.g.,

hunched over a desk or slouched over in front of a video game console); an

upright 90-degree sitting position; and a " relaxed " position where the

patient reclines backward 135 degrees while the feet remain on the floor.

Measurements were taken of spinal angles and spinal disk height and movement

across the different positions.

Spinal disk movement occurs when weight-bearing strain is placed

on the spine, causing the internal disk material to misalign.

The team saw that disk movement was most pronounced with a

90-degree upright sitting posture and was least pronounced with the

135-degree posture.

This they say indicates that less strain is placed on the spinal

disks and associated muscles and tendons in a more relaxed sitting position.

The " slouch " position revealed a reduction in spinal disk

height, signifying a high rate of wear and tear on the lowest two spinal

levels.

Across all measurements, the researchers concluded that the

135-degree position fared the best, and as a result, Dr. Bashir and

colleagues advise patients to ward off future back problems by correcting

their sitting posture and finding a chair that allows them to sit in an

optimal position of 135 degrees.

They suggest this may be all that is necessary to prevent back

pain, rather than trying to cure pain that has occurred over the long term

due to bad posture.

Dr. Bashir says employers could also reduce problems by

providing their staff with more appropriate seating, thereby saving on the

cost of lost work hours.

The research was presented at the annual meeting of the

Radiological Society of North America (RSNA).

http://www.news-medical.net/?id=21122

Not an MD

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org