Abstract: The invention relates to motorized adjustable back support for recliner chair comprising a back frame and means for transforming the power of a motor to a rotational movement of a horizontal rotation bar which is rotationally connected to the frame. The back support further comprises two adjustment arms each fixed on each side of the rotation bar close to the respective sides of the frame wherein the adjustments arms are parallel and have a flexible elongate unit stretching between their respective outer ends, and wherein the adjustment arms can move from a neutral to an extended position, corresponding to a rotation of the rotation bar.