Ergonomic Seat Height

I would like to initiate a dialogue about ergonomic seat height.

For the moment, let´s leave aside the issue of Mandal´s forward sloping seats which need to adjust higher, and assume that the seat pan is permanently fixed in a horizontal position.

Virtually all recommendations on seat pan adjustability have been based on people´s range of popliteal heights, and assume that the optimum seat height is achieved when the user sits with a 90° knee angle.

U.S., Canadian , and international preliminary seat guidelines are based on this posture.