Using positional MRI, researchers found that sitting upright in a 90 degrees posture is not the optimal seating position to reduce chronic back pain.
Dr. Waseem Amir Bashir and colleagues at the Woodend Hospital in Aberdeen, Scotland, measured intervertebral angles, heights, and movement across different positions on 22 normal subjects with no history of back pain or surgery. They found that sitting in an upright position places unnecessary strain on the back, leading to potentially chronic pain problems. The optimal sitting position creates a trunk-thigh angle of 135 degrees . This position was shown to cause least strain on the lumbar spine particularly when compared with a typical upright 90 degrees sitting posture.
