a fluid gases and in particular air are very suitable fluids liquids and gells could be used as well if desired turning to fig3 and 4 the advantages of the impact absorber of this invention are graphically illustrated in each of these figures a shoe 30 is shown together with foot 31 impacting downward into a heel pad shown as 32 in fig3 not according to the invention and as 10 in fig4 in accord with this invention in the case of heel pad 32 the downward pressure of the heel causes the center of the pad 34 to be severely depressed while permitting the edges 35 and 36 to balloon up this can be uncomfortable and unstable with pad 10 the center 33 depresses somewhat but there is minimal ballooning turning now to fig5 a variation of the core 11 is shown this core core 50 is fabricated from a plurality of foams of differing properties for example density as shown the core includes a series of plugs 51a 51b etc of firm density foam inserted into the body of core 11 this can result in a light weight core having the firmness of the plugs this is merely a representative.