Abstract: An office chair (1) including a seat (2), a backrest (3) including a lumbar support (4), an actuator device (8) arranged to enable adjustment of the lumbar support (4) between an inactive position in which it follows the general shape of the backrest (3), and a fully active position in which it is adjusted outwards forwardly from the backrest (3) in order to support the lumbar back portion of a person seated on the seat (2). The lumbar support (4) includes a first part (200) with first (201) and second (202) ends and a second part (300) with first (301) and second (302) ends. The first ends (201, 301) of the first and second parts (200, 300) are connected to each other via a pivoting point (400) and the second ends (202, 302) are pivotally coupled to the backrest (3), wherein at least one of the second ends (202, 302) of the parts (200, 300) is slidably arranged along the backrest (3) and wherein the actuator device (8) pushes and/or pulls the slidable ends (202, 302) in response to actuation.

Abstract: An office chair (1) comprising a seat (2) and a backrest (3), wherein the backrest (3) includes a lumbar support (4), which is adjustable between an inactive position in which it follows the general shape of the backrest (3), and a fully active position in which it is curved outwards forwardly from the backrest (3) in order to support the lumbar back portion of a person seated on the seat (2) of the chair (1).