Abstract: A lumbar support structure comprises a resilient grid formed of flexible vertical members and horizontal cross members. The grid is fixed in a seat, such as a car seat, and includes an upper back section and lumbar section. The lower end of the lumbar section is fixed and the upper end of the lumbar section is free and is coupled to cables connected to a cable wheel and clutch mechanism. Clutch mechanism rotates to wind the cable wheel and draw the cables to pull the free end of the lumbar section downward toward the fixed end. The lumbar section is bowed forwardly in the seat to provide lumbar support. The clutch mechanism comprises a clutch and locking pin which cooperate to rotate the cable wheel in both directions for adjusting the lumbar support. When the selected position for the lumbar support is chosen, the clutch is locked to maintain the bowed grid in a selected shape.