London:

If office colleagues begin to slide beneath their desks or flail hopelessly at out-of-reach keyboards, fear not. The latest medical advice on preventing back pain may be to blame.

Using advanced scanning equipment, doctors have concluded that the best way to avoid back pain is not to sit bolt upright but to perfect a more laid-back posture, a sprawl that is halfway between upright and horizontal.

Researchers at Woodend Hospital in Aberdeen used positional magnetic resonance imaging (MRI) capable of taking snapshots of 22 volunteers’ spines as they sat upright, slouched and hunched forward or laid back at an angle of 135 degrees. Traditional scanners require people to lie flat, which can mask the reasons they feel pain in different positions.

Desk slouchers, the images showed, are at high risk of causing wear and tear to spinal discs in their lower spine. But those sitting upright also fared badly. With the back vertical strain on the spine forced spinal disc material to shift out of line.

The safest posture, which put least strain on spinal discs and surrounding muscles and tendons, was the substantially more relaxed 135 degree backward sprawl, the researchers found.

“This may be all that is needed to prevent back pain, rather than trying to cure pain that has occurred over the long term due to bad posture,’’ said Waseem Bashir, a doctor on the study from the University of Alberta, Canada. “Employers could also reduce problems by providing their staff with more appropriate seating.”