THE COMBINATION OF A NEARLY RIGID STRONGLY RESILIENT BACKING BOARD FORMED OF A LAMINATED WOOD CORE AND RESIN BONDED FIBER GLASS SURFACES WITH A SHOCK-ABSORBING BUFFER MEMBER OF THE TYPE WHICH COMPRISES A RESILIENT HOLLOW BODY MEMBER NORMALLY FILLED WITH WATER HAVING ONE OR MORE OPENINGS, WHICH ARE NORMALLY CLOSED, FOR PERMITTING ESCAPE OF AT LEAST PART OF THE WATER IN A QUANTITY AND AT A LIMITED RATE ONLY COMMENSURATE WITH THE SEVERITY OF COLLISION IMPACT IS DISCLOSED.