A novel, flexible substrate assembly including a flexible substrate member having an inner surface and an outer surface, and a plurality of rigid or semi-rigid ribs associated with at least one of the inner and outer surfaces of the flexible substrate member. A chair assembly including a seat member, a back support member with an optional headrest, an optional left arm, an optional right arm, a floor-engaging base member which may form part of a frame assembly, a left side, a right side, a front side, and a back side, and a novel, flexible substrate assembly, wherein the novel flexible substrate assembly comprises a flexible substrate member having an inner surface and an outer surface, and a plurality of rigid or semi-rigid ribs associated with at least one of the inner and outer surfaces of the flexible substrate member.