A support comprising an outer casing having a main axis, the outer casing comprising a first casing part and a second casing part, the first casing part being at least partially receivable within the second casing part to enable relative movement therebetween in the axial direction, the casing parts having a cavity therein at least one of which has a core that includes a compressible medium, the support further including a pressure responsive system configured so that under the influence of pressure it can cause the relative displacement or movement between the first and second casing parts.