rods 38 the socket portions 32 of the ball and socket joints 28 28 u2032 are mounted on pads 40 that are affixed by adhesive for example to the side of the helmet 20 or to the top surface of the shoulder pads 22 each stem 34 of the upper ball and socket joints 28 is affixed to an annular member 42 which is rigidly mounted to the casing 44 of each cylinder 26 while the lower ball and socket joint 28 u2032 moves with the cylinder rod 38 ball and socket joints 28 28 u2032 of the type described above are referred to as quick disconnecting ball joint assemblies and are available from the superior linkage division of tuthill corporation of new haven ind usa 46774 both hydraulic cylinders 26 are in fluid communication with a valve 50 by means of flexile tubing 52 the valve 50 is preferably mounted to the back of the protective vest 26 between the shoulder pads 22 as illustrated in fig2 the preferred fluid used in the hydraulic circuit is a vegetable oil which is easily cleaned and environmentally friendly as can be appreciated the cylinders the tubing and the valve form a closed circuit this circuit has fill openings and or bleed valves which are.