Personnel

Don’t get your back up
By Maj Mike Tyquin

Volume 11, No. 60, February 22, 2007
 
Sit up: Cpl Andrew Hetherington, Army reporter, spends hours each day at his computer. A new study suggests he may be better off taking a relaxed position.
Photo by Lt Joseph Ternowetsky
SINCE early youth most of us have been raised in families where “sit up straight” was the order of the day.

Now the rationale for this parental favourite has been questioned by a new study that suggests leaning back is a better posture.

Researchers analysed different postures and concluded that the strain of sitting upright for long hours may cause long-term back problems. Using a new form of magnetic resonance imaging, 22 volunteers (with no back pain history) were studied in three different positions. These were slouching, sitting up straight at 90 degrees and sitting back at 135 degrees. While they did this their backs were scanned.

According to the study’s author, Waseem Amir Bashir, of Canada’s University of Alberta Hospital, a 135-degree body-thigh sitting posture was demonstrated to be the best biomechanical sitting position, as opposed to a 90-degree posture, which most people consider normal.

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.

Despite the fact that the human being is not engineered to sit down for long hours, many of us spend many hours a day working in a seated position. The scanning procedure found that when strain is placed on the spine, the spinal discs started to move and misalign.

At a 90-degree sitting position, this movement was most prominent. However, the disks were least moved when subjects were sitting back at a 135-degree sitting position.

Sitting on a chair that provides proper support, such as a slightly tilted back car seat, can mimic the relaxed supine or lying position. Slouching caused a reduction in the spinal height which meant that there was a high rate of wear and tear in the lowest two spinal levels.