a shock absorber comprising a cylinder closed at one end and resiliently deformable radially outwards at a predetermined internal pressure , a resilient liner within the cylinder in intimate contact with the wall of the cylinder , a fluid - tight seal at the open end of the cylinder , a piston rod extending through the seal , a piston in the cylinder and connected to the rod and in sliding engagement with the inner wall of the liner , an impact receiving member on the free end of the rod outside the cylinder ; a liquid of predetermined flow characteristics in the cylinder , and at least one zone extending over a substantial length of the stroke of the piston and having a cross section varying over at least part of the length to form a single free liquid flow path past the piston , the configuration of the zone , the flow characteristics of the liquid , the pressure in the closed end of the cylinder and the resilience of the material of at least one of the cylinder and the liner resulting in shocks being absorbed by the shock absorber in accordance with predetermined characteristics .