World-renowned mobility experts such as Kelly Starrett, Mark Verstegen, and Esther Gokhale have written about the huge role that posture plays in overall health. Kelly describes sitting as the new smoking is his new book "Deskbound". External rotation and thoracic mobility is a key part of maintaining correct posture. Learn more from Kelly here.
Traditional chair backs actually encourage poor thoracic posture.
Backplane gives your shoulders the room they need to externally rotate.