Sitmatic | The freedom of movement that this back allows eliminates awkward postures when reaching about the workstation. The spine is well supported, shoulder blades automatically stretch back, and arms are free to move. Pain in the upper back region is often the result of tight muscles or injury to the rotator cuff. By allowing the elbows to sit slightly behind body you are retracting the shoulder blades to allow a more relaxing posture. Libre™ also allows the user to actively engage in shoulder stretching. Libre™, feel free to move!