A linkage extension system, comprising: a movable cross member of a seat, the movable cross member configured to be movably coupled to a stationary member of the seat, the stationary member configured to be rigidly coupled to the seat, the movable cross member configured to translate along a movement plane to at least one of an extended position, a retracted position, and at least one intermediate position, the retracted position proximal to the seat and the extended position and at least one intermediate position distant from the seat; a pair of lower links rotationally coupled at a lower pivot joint with the stationary member, the pair of lower links configured to rotate within the movement plane; a pair of upper links rotationally coupled at an upper pivot joint with the movable cross member, the pair of upper links configured to rotate within the movement plane, the upper links and the lower links coupled to each other via a link pivot joint; and at least one damper operably coupled to at least one of: 1) the movable cross member, 2) at least one lower link, 3) at least one upper link, 4) at least one link pivot joint and 5) the stationary member; the at least one damper configured to provide a holding force, the holding force restricting translation of the movable cross member as the movable cross member is in one of: the extended position, the retracted position and the at least one intermediate position, characterized in that the at least one damper further comprises at least one of: - at least one first rotary damper rigidly coupled to the stationary member and operably coupled with at least one lower link, the at least one rotary damper providing the holding force directly upon the at least one lower link; and. - at least one second rotary damper (214, 312) rigidly coupled to the movable cross member and operably coupled to at least one upper link, the at least one rotary damper (214, 312) providing the holding force directly upon the at least one upper link. a movable cross member of a seat, the movable cross member configured to be movably coupled to a stationary member of the seat, the stationary member configured to be rigidly coupled to the seat, the movable cross member configured to translate along a movement plane to at least one of an extended position, a retracted position, and at least one intermediate position, the retracted position proximal to the seat and the extended position and at least one intermediate position distant from the seat; a pair of lower links rotationally coupled at a lower pivot joint with the stationary member, the pair of lower links configured to rotate within the movement plane; a pair of upper links rotationally coupled at an upper pivot joint with the movable cross member, the pair of upper links configured to rotate within the movement plane, the upper links and the lower links coupled to each other via a link pivot joint; and at least one damper operably coupled to at least one of: 1) the movable cross member, 2) at least one lower link, 3) at least one upper link, 4) at least one link pivot joint and 5) the stationary member; the at least one damper configured to provide a holding force, the holding force restricting translation of the movable cross member as the movable cross member is in one of: the extended position, the retracted position and the at least one intermediate position, characterized in that the at least one damper further comprises at least one of: - at least one first rotary damper rigidly coupled to the stationary member and operably coupled with at least one lower link, the at least one rotary damper providing the holding force directly upon the at least one lower link; and. - at least one second rotary damper (214, 312) rigidly coupled to the movable cross member and operably coupled to at least one upper link, the at least one rotary damper (214, 312) providing the holding force directly upon the at least one upper link. - at least one first rotary damper rigidly coupled to the stationary member and operably coupled with at least one lower link, the at least one rotary damper providing the holding force directly upon the at least one lower link; and. - at least one second rotary damper (214, 312) rigidly coupled to the movable cross member and operably coupled to at least one upper link, the at least one rotary damper (214, 312) providing the holding force directly upon the at least one upper link.