(Reuters Health) – “Sit up straight — you’ll hurt your back,” Mom always said. It turns out Mom was wrong, according to a new study that found sitting in an upright 90-degree position places more strain on the back than sitting in a slightly reclined 135-degree position.
“Everybody knows that if you sit for long periods you have back pain,” Dr. Waseem Amir Bashir, a radiologist from the University of Alberta Hospital in Canada told Reuters Health.
To search for the optimal back-friendly sitting position, Bashir and colleagues used a “positional” MRI scanner to study 22 healthy adults with no history of back pain or back surgery as they sat in three different positions: a slouching position in which the body is hunched forward, like over a keyboard; an upright straight-back position with legs at 90-degrees and knees and hips at the same level; and a “relaxed” 135-degree tilt back position. “In this position, the legs are lower than the hips and the back is slightly forward with a normal curvature which provides lumbar support,” Bashir explained.
“We found that the reclined 135-degree position is the ideal sitting position because it actually is similar to a neutral relaxed lying down position,” Bashir told Reuters Health.
Potentially harmful spinal disk movement was most pronounced with the 90-degree sitting position; it was least pronounced with the 135-degree relaxed position, indicating that less strain is placed on the spine and associated muscles and tendons in this position.