Abstract: A seat back suitable for a vehicle incorporates a mechanically adjustable lumbar support. A flexible panel (9) is mounted by hooks (8) on a rigid frame (6). In the lumbar region pockets (13) formed at the margins of the panel house the central regions (15) of strip spring steel springs (16). The upper and lower ends of each spring curve rearwardly from the panel. The upper ends are interconnected by a cross member (18) and the lower ends are interconnected by a cross member (19). A Bowden cable (22) controlled by a manual or powered actuator is provided for moving the cross members (18, 19) towards each other and thereby causing the central regions (15) of the strip springs to bow outwardly and increase the amount of lumbar support provided by the panel region therebetween.