The present invention relates to sliding supports and particularly sliding supports having two elongate members of channel section which slide one within the other. The invention address the problem of using such sliding supports in an orientation where the channels of the elongate members open vertically rather than horizontally. The sliding support preferably includes a damping mechanism for resisting relative sliding movement of the elongate members. The sliding support also preferably includes a mechanism for defining one or more intermediate positions between extended and shortened positions of the sliding support.