Joint arrangement (10) has a hollow cylindrical receiving cylinder (20) that extends in a cylinder axis direction (Z) and receives one end of a chair column (30) of an active-dynamic wobble chair, the latter movably mounted in a substantially hollow cylindrical outer joint shell (40) composed of joint shell segments (45). Movable mounting of receiving cylinder (20) is achieved by deformable elastic elements (50) arranged to be variable in shape and position in a bearing gap (60) between an outer wall portion (21, 22) of the receiving cylinder (20) and an inner wall portion (41, 42) of the joint shell (40). Receiving cylinder (20) is actuated in a force-dependent manner, whereby shape and/or position of the elastic elements (50) change as viewed in a radial direction (Rs) from changing, preferably reducing, clearance of the bearing gap (60) when the receiving cylinder (20) is actuated in a cylinder axis direction (Z).

The chair of the present disclosure includes a base, a seating surface positioned on the upper side of the base and seated by a user, a base and a seating surface are connected, a seating surface is maintained in a reference state, and a seating surface is inclined from the reference state in accordance with a force applied to the seating surface by the seating of the user in accordance with the reference state; an elastic support post installed on the upper side of the base and rotating about an axis in the vertical direction based on power; a plurality of support posts installed on the upper side of the rotating table and supporting the seating surface at the upper end portion when the seating surface is inclined; and a motor that generates power.