What is the best angle between the back and the back of the chair?
In the case of the human spine, this angle is more appropriate at 115 degrees, and it produces a shape closer to the natural waist. In sitting posture, the best angle of reading is 101 - 104 degrees, and the 105 - 108 degree is more relaxing.
Back angle: 103 - 112 degrees. The angle between the back and the cushion also has two purposes to prevent the sitting body from sliding forward and to guide the lumbar bend (including the sacrum), depending on the back.
