A chair back assembly includes a frame assembly including a pair of slots extending through the frame assembly, a first location positioned between the pair of slots, and a pair of second locations located outward of an outer periphery of the frame assembly, and a vertically adjustable lumbar assembly configured to support a lumbar area of a seated user and including a central portion and a pair of end portions slidably engaging the central portion, the central portion located in the first location and the end portions located in the second locations, wherein the pair of end portion are slidably moveable within the slots between a first position and a second position that is different than the first position.