A seating unit that includes an adjustable foundation, a torque-inducing mechanism, and a base structure for interconnecting a backrest and a seat is provided. The adjustable foundation provides adjustable support for, and is controlled by, an occupant of the seating unit. The adjustable foundation includes extensible supports that each have a first and second end, and a frame assembly. The frame assembly includes a stationary member that is fixedly attached to the first ends and a drive bar that is configured to secure the second ends of the extensible supports such that longitudinal tension is generated upon rotating the drive bar with respect to the stationary member. The torque-inducing mechanism adjusts an angular position of the drive bar. In this capacity, the drive bar is configured to convert torque applied by the torque-inducing mechanism into a directional force that controls the longitudinal tension of the extensible supports.