Sitting straight is not the best positions for office workers, a Scottish study has suggested.
The study, conducted by Scottish and Canadian researches, used a new form of magnetic resonance imaging (MRI) to show that sitting straight placed unnecessary strain on your back.
Their study found that the best position in which to sit at your desk is leaning back, at about 135 degrees.
Twenty two volunteers with healthy backs were scanned using a positional MRI machine, which allows patients the freedom to move - so they can sit or stand - during the test.
Traditional scanners mean patients have to lie flat, which may mask causes of pain that stem from different movements or postures.
In this study, the patients assumed three different sitting positions: a slouching position, in which the body is hunched forward as if they were leaning over a desk or a video game console, an upright 90-degree sitting position; and a "relaxed" position where they leaned back at 135 degrees while their feet remained on the floor.
The researchers then took measurements 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 disk to move out of place.
Disk movement was found to be most pronounced with a 90-degree upright sitting posture.
It was least pronounced with the 135-degree posture, suggesting 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.
When they looked at all test results, the researchers said the 135-degree position was the best for backs, and say this is how people should sit.