referring to fig1 a running shoe generally designated 1 is shown . the shoe 1 includes a sole 2 and an upper 3 secured to the sole , the upper ( as is conventional ) including a reinforced counter or heel cup surrounding the heel portion of the shoe . the sole has a synthetic rubber base 4 in which a tread pattern of gripping elements or cleats is formed . the base 4 is attached , for example by means of adhesive or by welding , to a first resilient midsole layer 5 which is in turn attached to a further resilient midsole layer 6 , for example by means of adhesive or by welding . the midsole layers 5 , 6 may be formed of foamed plastic materials and could , if desired , be formed in one piece rather than as two separate pieces . a further resilient heel wedge layer 7 formed from foamed plastic material is provided at the heel end of the shoe 1 . the layer 7 raises the heel portion of the shoe and may be attached to the layer 6 by means of adhesive or by welding , for example , and may be formed all in one piece or alternatively may be formed in two or more longitudinally extending pieces which advantageously can have increasing durometer hardnesses towards the peripheral edges of the heel to ensure lateral stability throughout the life of the shoe . the complete sole 2 may be secured to the upper 3 by means of adhesive , for example , and a removable insole or foot - bed 8 is provided within the shoe . further shown in fig1 is the provision of resilient spherical bodies in the sole of the shoe at the heel and at the ball of the foot . at the heel portion of the shoe there is formed a recess 9 defined by holes punched in the mid - sole layers 5 , 6 and in the inserted heel wedge 7 , and a resilient spherical body 10 is inserted into the recess 9 as shown . the spherical body 10 sits within the recess 9 with its lower surface in tangential contact with the upper surface of the outer sole 4 and its upper surface projecting slightly above the upper surface of the heel wedge 7 for tangentially contacting the underside of the removable insole 8 . further recesses 11 are provided , in a similar manner , at the front portion of the sole in the region of the ball of the wearer &# 39 ; s foot , these further recesses as shown being of smaller diameter and greater number than the recess 9 in the heel and being arranged in two or three or more rows each of a plurality of recesses as shown in fig2 and resilient spherical bodies 12 of smaller diameter than the one provided in the heel are accommodated in respective ones of these recesses . as described hereinafter , the resilient spherical bodies 10 , 12 have the function of determining the elasticity characteristics of the shoe . fig2 shows a top plan view of the shoe sole 2 and illustrates the arrangement of the recesses 11 in the region of the ball of the foot , it being understood that the illustrated arrangement is exemplary only . the resilient spherical bodies 10 , 12 , or at least some of them , are preferably gas - filled pneumatic bodies , and preferably are provided with an inflation valve port 13 whereby , as shown in fig3 air may be pumped into or released from the respective spherical body 10 , 12 by means of an air pump 15 , thus to increase or decrease the hardness characteristics of the spherical body for matching the shoe to the body weight and individual requirements of the wearer . this facility is advantageous particularly in the course of a long run , such as a marathon , or a long game , since it enables the shoe characteristics to be adjusted during the run or during the game to take account of different conditions and changing levels of fatigue . on a long run , running shoes can become up to 15 ° c . hotter than at the start of the run , on account of friction effects , which can cause the inflatable bodies 10 , 12 to become undesirably firm and insufficiently cushioning . this problem can be overcome , in accordance with the invention , by adjusting the pressure of the inflatable bodies . in use of a sports shoe constructed in accordance with the present invention , the presence of the resilient bodies provides excellent cushioning and protection against shock , and also provides a resilience to the shoe characteristics which is invigorating and beneficial , the resilience of the spherical bodies as they resile from their compressed states as the foot is lifted providing a positive spring to the step of the wearer . fig4 shoes schematically a form of shoe sole in accordance with the invention which has a plurality of recesses 16 provided in the heel region of the sole , each recess being of lesser size than the corresponding heel recess provided in the shoe of fig1 and has a plurality of pneumatic bodies 17 provided in each recess , some at least of such bodies being selectively inflatable and deflatable . one effect of this arrangement is to provide a more uniform distribution throughout the heel area of the shoe sole of the advantageous effects provided by the arrangement of fig1 . referring now to fig5 and 6 of the drawings , the shoe shown schematically therein comprises an upper 21 and a sole 22 , the sole comprising a rubber outsole layer 23 , a midsole 24 formed of one or more layers of compression molded eva , for example , an insole 25 formed of texon board , for example , and a removable footbed 26 which desirably is reinforced so as to contribute to the lateral stability of the shoe , for example by being transversely ridged . as shown , an opening 27 is provided in the insole 25 in registry with a recess 28 formed in the midsole 24 , a reinforcing piece of texon board 29 is provided in the bottom of the recess 28 , and a gas - filled member 30 is received partially within the recess 28 . the gas - filled member 30 as shown has a domed upper or head portion 31 of greater transverse dimension than the opening 27 provided in the insole 25 so that such head portion 31 does not fit into the recess 28 formed in the midsole 24 , but rather rests upon the upper surface of the texon insole 25 around the periphery of the opening 27 and defines an upwardly domed gas cushion seated on the insole . a body portion 32 of the gas - filled member 30 is of generally cylindrical shape , with concertina side walls as shown and a flat base , and fits into the recess 28 formed in the midsole 24 . the gas - filled member 30 is preferably arranged to be removable from its accommodating recess in the shoe sole , and different members having different gas pressures can be made available whereby the shoe can be configured to suit the requirements of the user . additionally , or alternatively , the gas - filled member 30 can as shown be provided with a valve 33 enabling it to be selectively inflated or deflated . the concertina - pleated side walls of the gas - filled member 30 provided the advantage that the pneumatic resilience of the member is substantially unidirectional and in the axial direction of its accommodating recess , which is advantageous as regards the stability of the shoe . the lateral edges of the midsole 24 , at least in the region of the heel of the shoe , may be of greater durometer hardness than the central midsole region to ensure that the lateral stability of the shoe is maintained during the life of the shoe . this is indicated schematically in fig6 by the shaded lateral areas of the midsole 24 and might , for example , be achieved by forming the midsole of a number of different portions formed of different density materials and adhered together . the gas - filled member 30 can be made in the form of a single hollow gas - filled sac formed of a suitable synthetic plastic material , or could be a composite body formed as a plurality of gas - filled sacs adhered together . alternatively , the gas - filled member 30 could be formed in whole or in part as a closed - cell foamed plastic structure . additionally , pneumatic resilience could be provided in the ball of the foot region of the shoe by incorporation therein of resilient bodies similar to the member 30 or of any other suitable shape and form . furthermore , while fig5 and 6 show the provision of only one resilient member 30 in the heel of the shoe , it will be appreciated that more than one such member could be provided . while the invention has been described herein in relation to specific embodiments , it is to be well understood by those skilled in the art that the invention can be embodied in other forms . for example , the resilient bodies provided in the shoe sole can be of virtually any shape that is capable of providing cushioning ; they could comprise , for example , circular disc shaped bodies , oval or egg shaped hemispherical bodies , cylindrical bodies , rectangular or etc . furthermore , the resilient bodies need not be inflatable , but could , for example , comprise solid elastomeric material .
an improved structure of the sole of shoes suitable for use in sports or any casual wear is characterized in that the mid - sole is provided with resilient spherical bodies within recesses in the front portion and / or the heel portion of the sole , and that the hardness of the resilient bodies can be adjusted to enhance the elasticity of the soles of the shoes by virtue of the fact that the spherical bodies can be inflated and deflated or can be bodily replaced , thereby enabling the requisite shock absorbing effect to relieve impact stress during running and fatigue during long walking to be obtained .