Patent Publication Number: US-11388952-B2

Title: Shoe with reinforcement device for reinforcing an upper

Description:
TECHNICAL FIELD 
     The present invention relates to a shoe including a reinforcement device reinforcing a heel portion of an upper. 
     BACKGROUND ART 
     A heel counter, which is an example of a reinforcement device, covers the opposite side surfaces and the rear surface of the heel and maintains the shape of the heel portion of the upper. When the entire heel is wrapped around by the heel counter formed from a resin part, the heel portion of the upper has a high rigidity, but it inhibits the deformation of the upper in conformity with the shape of the heel of the wearer. That is, the fitting property of the heel portion deteriorates. 
     For example, heel counters formed in lattice shapes are known in the art, as described in the patent documents identified below. Moreover, heel counters having different shapes on the lateral side and on the medial side are known in the art. 
     CITATION LIST 
     Patent Literature 
     First Patent Document: WO2010/038267 A1 (FIGS. 1 and 2) 
     Second Patent Document: JP2005-296101/A1 (FIG. 3) 
     SUMMARY OF INVENTION 
     It is an object of the present invention to provide a reinforcement device of an upper of a shoe that improves the stability property and the following property (the conforming property) of the shoe from landing to takeoff while running. 
     A shoe in one aspect of the present invention includes: an upper  1 , a reinforcement device  4  reinforcing the upper  1 , and a sole  2  attached to the upper  1 , wherein: 
     the upper  1  includes a lateral side boundary portion  120  between the upper and the sole  2  on a lateral side  12  of the upper, a medial side boundary portion  110  between the upper and the sole  2  on a medial side  11  of the upper, and a rear boundary portion  10  between the upper and the sole  2  in a rear end portion  15  of the upper; 
     the medial side boundary portion  110  and the lateral side boundary portion  120  are continuous with each other via the rear boundary portion  10 ; and 
     the reinforcement device  4  includes: 
     a rear first portion B 1  placed between the sole  2  and a top line (a collar or a wearing opening)  20  of the upper  1  in a rear end portion  15  of the upper; 
     a rear second portion B 2  placed in the rear boundary portion  10 ; 
     a lateral first portion L 1  being continuous with the rear first portion B 1  and extending toward the sole  2  on the lateral side  12  of the upper; 
     a medial first portion M 1  being continuous with the rear first portion B 1  and extending toward the sole  2  on the medial side  11  of the upper, the medial first portion M 1  being less flexurally deformable than the lateral first portion L 1 ; and 
     a medial second portion M 2  being continuous with the rear second portion B 2  and extending toward an anterior direction from the rear second portion B 2  along the medial side boundary portion  110  on the medial side  11  of the upper so that the medial side boundary portion  110  is less flexurally deformable than the lateral side boundary portion  120 . 
     With ordinary athletic shoes, a resin-made or resin-impregnated member, called a heel counter, is arranged on the medial and lateral sides of the heel portion. A heel counter maintains the shape of the shoe, and suppresses the pronation of the subtalar joint that occurs during the support period after landing. The flexural rigidity of the medial side of the heel counter substantially contributes to the suppression of the pronation, and it serves to support, by means of the medial side of the upper, the foot being urged to collapse toward the medial side. The medial first portion M 1  and the medial side boundary portion  110 , which are less flexurally deformable than the lateral first portion L 1 , will serve to suppress the pronation and improve the stability property. 
     The foot, which lands starting from the lateral side of the heel portion, exhibits pronation thereafter. The lateral side boundary portion  120  is more flexurally deformable and more compressively deformable than the medial side boundary portion  110 , thereby increasing the amount of deformation of the lateral side boundary portion  120  upon heel contact. As a result, it is expected to suppress the speed at which the foot collapses toward the medial side and decrease the pronation to be exhibited thereafter. 
     In the latter half of the support period, the heel rises entailing the weight transfer, the forefoot portion of the sole dorsiflexes, and a restoring force occurs in the sole in such a direction that urges the rearfoot portion of the sole away from the foot. At this point, the upper is required to have a good foot fitting property, and particularly, the heel portion of the sole and that of the upper are required to have a good foot following property during the latter half of the support period. At this point, the force that acts upon the upper from the foot is a force that pushes the back side (the rear end portion) of the heel portion of the upper in the direction normal to the upper surface. Therefore, there is a demand for the back side of the heel portion of the shoe to have a structure that suppresses the deformation against such a force. 
     In view of this demand, in the present invention, the rear first portion and the rear second portion placed on the rear end portion of the upper increase the rigidity of the back side of the heel portion, thereby suppressing the deformation of the heel portion. This will improve the following property. 
     The lateral first portion L 1 , which is more flexurally deformable than the medial first portion M 1 , extends from the rear first portion B 1  toward the sole  2 . Therefore, the lateral first portion L 1  suppresses the stretch of the heel portion lateral side in the direction that connects between the lower portion of the upper below the ankle and the rear first portion B 1  without excessively increasing the flexural rigidity of the heel portion lateral side. This suppresses the deformation due to a force that pushes the back side (the rear end portion) of the heel portion of the upper in the direction normal to the upper surface. This as a result will improve the following property. 
     As described above, the present invention is expected to improve the stability property and the foot following property during the support period. 
     The rear first portion and the rear second portion increase the rigidity of the back side of the upper. In view of this, “the rear end portion of the upper”, where the rear first portion and the rear second portion are placed, means an extent of 20% or less extending from the rear end of the upper with respect to the entire length (the length of the shoe in the longitudinal direction) 100% of the upper on the sagittal plane. This is because when the reinforcement device is placed in such an extent, it is possible to increase the rigidity of the back side of the upper. Therefore, it is preferred that at least a portion of the rear first portion and the rear second portion is placed in the rear end portion, which is the 20% extending from the rear end of the upper. It is preferred that at least a portion of the rear first portion is placed in an extent of 10% or less from the rear end of the upper and at least a portion of the rear second portion is placed in an extent of 20% or less. It is more preferred that at least a portion of the rear first portion is placed in an extent of 10% or less from the rear end of the upper and at least a portion of the rear second portion is placed in an extent of 15% or less. It is particularly preferred that at least a portion of the rear first portion and at least a portion of the rear second portion are both placed in an extent of 10% or less from the rear end of the upper. 
     The medial side refers to the side that is closer to the median on the frontal plane of the body, and is commonly referred to often as the inner side or the inner side of the foot. The lateral side refers to the side that is farther away from the median on the frontal plane of the body, and is commonly referred to often as the outer side or the outer side of the foot. 
     Being less flexural deformable includes cases where the flexural rigidity ∫EIz is higher, and also cases where the reinforcement device is formed in a loop shape and has less deformation due to bending moment. 
     The flexural rigidity means the integral value ∫EIz of the Young&#39;s modulus (longitudinal elastic modulus) E and the moment of inertia of area Iz of the member. 
     Each first portion and the corresponding second portion may be vertically continuous with each other or vertically separated from each other. The medial first portion and the medial second portion may have a window (through hole) therebetween, or may be continuous with each other in a flat plate shape. A lateral second portion having a thin plate shape may be provided also on the lateral side. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic side view of the medial side showing an athletic shoe of Embodiment 1 of the present invention. 
         FIG. 2  is a schematic side view of the lateral side showing the athletic shoe of Embodiment 1. 
         FIG. 3  is a back view showing the athletic shoe of Embodiment 1. 
         FIG. 4  is a IV-IV cross section of an upper according to Embodiment 1. 
         FIG. 5  is a V-V cross section of the upper according to Embodiment 1. 
         FIG. 6  is a side view and a back view of the lateral side showing 5 types of shoes used in a test. 
         FIG. 7  is a bar graph showing the measurement result of the heel eversion angle ß after landing. 
         FIG. 8  is a bar graph showing the measurement result of the lower leg internal rotation angle (the lower leg inversion angle) γ after landing. 
         FIG. 9  is graphs showing the measurement method and the measurement result of the displacement of the heel with respect to the shoe. 
         FIG. 10A  is a side view of the medial side of the rearfoot portion of a shoe according to Embodiment 2, and  FIG. 10B  is a side view of the lateral side of the rearfoot portion of the shoe according to Embodiment 2. 
         FIG. 11A  is a side view of the medial side of the rearfoot portion of a shoe according to Embodiment 3, and  FIG. 11B  is a side view of the lateral side of the rearfoot portion of the shoe according to Embodiment 3. 
         FIG. 12A  is a side view of the medial side of the rearfoot portion of a shoe according to Embodiment 4,  FIG. 12B  is a back view of the shoe according to Embodiment 4, and  FIG. 12C  is a side view of the medial side of the rearfoot portion of the shoe according to Embodiment 4. 
         FIG. 13A  and  FIG. 13B  are side views of the medial side and the lateral side, respectively, showing another example of a heel counter. 
         FIG. 14  is a side view of the lateral side showing other seven types of heel counters used in a test. 
         FIG. 15  is a bar graph showing the measurement result of the heel eversion angle ß after landing from the test. 
         FIG. 16  shows the relationship between the cut-off percentage in the vertical direction or the foot longitudinal direction and the angle ß. 
         FIG. 17  is a schematic side view of the medial side showing an athletic shoe of Embodiment 6 of the present invention. 
         FIG. 18  is a schematic side view of the lateral side showing the athletic shoe of Embodiment 6. 
         FIG. 19  is a back view showing the athletic shoe of Embodiment 6. 
         FIG. 20A  is a XXA-XXA cross section of an upper according to Embodiment 6, and  FIG. 20B  is a XXB-XXB cross section of the upper according to Embodiment 6. 
         FIG. 21  is a perspective view of a heel counter according to Embodiment 6 as seen from the medial side. 
         FIG. 22  is a schematic side view of the medial side showing an athletic shoe of Embodiment 7 of the present invention. 
         FIG. 23  is a schematic side view of the lateral side showing the athletic shoe of Embodiment 7. 
         FIG. 24  is a perspective view showing a heel counter of Embodiment 7. 
         FIG. 25A  is a XXVA-XXVA cross section of an upper according to Embodiment 7, and  FIG. 25B  is a XXVB-XXVB cross section of the upper according to Embodiment 7. 
         FIG. 26  shows a medial side view, a bottom view, a lateral side view, a vertical section, an e-e cross section, an f-f cross section and an enlarged cross section showing the heel counter of Embodiment 7. 
         FIG. 27  relates to another example of a built-in heel counter, and is a lateral side view showing the structure of a low-rigidity portion of the lateral side. 
         FIG. 28  relates to another example of a built-in heel counter, and is a plan view showing an unmolded state. 
         FIG. 29  is a medial side view and a lateral side view showing another example of an external heel counter. 
         FIG. 30  is a lateral side view and a medial side view showing still another example of an external heel counter. 
     
    
    
     In  FIG. 1  to  FIG. 6 ,  FIG. 10A  to  FIG. 13A ,  FIG. 17  to  FIG. 20A ,  FIG. 25A  and  FIG. 25B , heel counter areas are dotted. 
     DESCRIPTION OF EMBODIMENTS 
     Preferably, the lateral first portion L 1  extends toward the sole  2  and toward the anterior direction reaching the sole  2 , the lateral first portion L 1  (the reinforcement device  4 ) further including a lateral tucked end portion LE tucked between the sole  2  and the upper  1 . 
     The lateral tucked end portion of the lateral first portion is tucked between the sole and the upper, and the lateral first portion increases the tensile rigidity between the lower end of the upper and the rear end portion of the upper below the lateral malleolus of the heel portion. This will improve the following property. 
     Preferably, the reinforcement device  4  includes a heel counter  4  made of a thermoplastic resin; and 
     the heel counter  4  includes the rear first portion B 1 , the rear second portion B 2 , the medial first portion M 1  and the medial second portion M 2 , which are integrally continuous with each other. 
     In this case, it is easy to manufacture the reinforcement device. 
     Preferably, the heel counter  4  further integrally (and seamlessly) includes the lateral first portion L 1 . 
     In this case, it is even easier to manufacture the reinforcement device. 
     Preferably, a moment of inertia of area of the medial first portion M 1  is greater than a moment of inertia of area of the lateral first portion L 1 . 
     The moment of inertia of area Iz of the lateral first portion L 1  is smaller than the moment of inertia of area Iz of the medial first portion M 1 . Therefore, it is easy to lower the flexural rigidity of the upper on the lateral side of the heel portion. As a result, the pronation will be decreased as described above. 
     Preferably, the lateral first portion L 1  is formed from a tape material separate from the heel counter  4 . 
     The tape material has a lower flexural rigidity than the heel counter, and gives a high tensile rigidity. Therefore, the upper on the lateral side of the heel portion has a low flexural rigidity, thereby decreasing the pronation. Since the tensile rigidity is high, a high following property will be exhibited. 
     Preferably, the heel counter  4  is absent (not provided) in the lateral side boundary portion  120  of the upper  1 . 
     In this case, the flexural rigidity on the lateral side of the heel portion is low. 
     A shoe in another aspect of the present invention includes: an upper  1 , a reinforcement device  4  reinforcing the upper  1 , and a sole  2  attached to the upper  1 , wherein: 
     the upper  1  includes a lateral side boundary portion  120  between the upper and the sole  2  on a lateral side  12  of the upper, a medial side boundary portion  110  between the upper and the sole  2  on a medial side  11  of the upper, and a rear boundary portion  10  between the upper and the sole  2  in a rear end portion  15  of the upper; 
     the medial side boundary portion  110  and the lateral side boundary portion  120  are continuous with each other via the rear boundary portion  10 ; and 
     the reinforcement device  4  includes: 
     a rear first portion B 1  placed between the sole  2  and a top line (a collar)  20  of the upper  1  in a rear end portion  15  of the upper; 
     a rear second portion B 2  placed in the rear boundary portion  10 ; 
     a lateral first portion L 1  being continuous with the rear first portion B 1  and extending toward the sole  2  on the lateral side  12  of the upper; 
     a medial first portion M 1  being continuous with the rear first portion B 1  and extending toward the sole  2  on the medial side  11  of the upper; and 
     a medial second portion M 2  being continuous with the rear second portion B 2  and extending toward an anterior direction from the rear second portion B 2  along the medial side boundary portion  110  on the medial side  11  of the upper, wherein: 
     the lateral first portion L 1  extends toward the sole  2  and toward the anterior direction reaching the sole  2 , the lateral first portion L 1  including a lateral tucked end portion LE tucked between the sole  2  and the upper  1 ; 
     the rear second portion B 2  extends to the sole  2 , the rear second portion B 2  including a rear tucked end portion BE tucked between the sole  2  and the upper  1 ; and 
     the medial second portion M 2  includes a medial tucked end portion ME that is tucked between the sole  2  and the upper  1  and connects together the rear second portion B 2  and a lower end portion of the medial first portion M 1 . 
     In this aspect, the medial second portion M 2  extending along the medial side boundary portion  110  includes the medial tucked end portion ME that connects between the rear second portion B 2  and the lower end portion of the medial first portion M 1 , and is therefore less flexural deformable as compared with the lateral side. 
     The reinforcement device  4  having such a structure maintains the shape of the shoe, and suppresses the pronation of the subtalar joint that occurs during the support period after landing. Therefore, it serves to support, by means of the medial side of the upper, the foot being urged to collapse toward the medial side. 
     The foot, which lands starting from the lateral side of the heel portion, exhibits pronation thereafter. The upper on the lateral side having the lateral tucked end portion LE is more flexurally deformable as compared with the upper on the medial side having the medial tucked end portion ME that connects together the rear second portion B 2  and the lower end portion of the medial first portion M 1 . 
     That is, the lateral side boundary portion  120  is more flexurally deformable than the medial side boundary portion  110 , thereby increasing the amount of deformation of the lateral side boundary portion  120  upon heel contact. As a result, it is expected to suppress the speed at which the foot collapses toward the medial side and decrease the pronation to be exhibited thereafter. 
     As described above, in the latter half of the support period, the rear first portion B 1  and the rear second portion B 2  placed in the rear end portion of the upper increase the rigidity on the back side of the heel portion, thereby suppressing the deformation of the heel portion. This will improve the following property. 
     The lateral first portion L 1  is more flexurally deformable as compared with the medial side having the medial tucked end portion ME. The lateral first portion L 1  suppresses the stretch of the heel portion lateral side in the direction that connects between the lower portion of the upper and the rear first portion B 1  below the ankle without excessively increasing the flexural rigidity of the heel portion lateral side. This suppresses the deformation due to a force that pushes the back side (the rear end portion) of the heel portion of the upper in the direction normal to the upper surface. This as a result will improve the following property. 
     As described above, the present invention is expected to improve the stability property and the foot following property during the support period. 
     Preferably, the reinforcement device  4  includes a heel counter  4  made of a thermoplastic resin; 
     the heel counter  4  is attached to an outer surface of the upper  1 ; and 
     the heel counter  4  includes a rear first portion B 1 , a rear second portion B 2 , a lateral first portion L 1 , a medial first portion M 1  and a medial second portion M 2 , which are integrally and seamlessly continuous with each other. 
     In this case, it is easy to manufacture the reinforcement device  4 . 
     Preferably, a rear end of the lateral tucked end portion LE and a front end of the rear tucked end portion BE are unconnected and separated from each other in an anterior-posterior direction. 
     In this case, the upper on the lateral side has a lower flexural rigidity as compared with the upper on the medial side having the medial tucked end portion ME. As a result, the pronation will be decreased as described above. 
     Preferably, the heel counter  4  includes a lateral bridge  42  that extends toward a diagonal anterior-upward direction from the rear second portion B 2  to the lateral first portion L 1 ; and 
     a low-rigidity portion is provided between the lateral bridge  42  and the sole  2 , the low-rigidity portion having a rigidity lower than that of the lateral bridge  42 . 
     With the structure that includes a low-rigidity portion between the lateral bridge  42  and the sole  2 , it is easy to lower the flexural rigidity of the lateral side boundary portion  120 . Therefore, with such a structure, it is easy to decrease the pronation. 
     Preferably, the heel counter  4  includes a lateral bridge  42  that extends toward a diagonal anterior-upward direction from the rear second portion B 2  to the lateral first portion L 1 ; and an exposed portion  121  is provided between the lateral bridge  42  and the sole  2 , and the lateral side boundary portion  120  of the upper  1  is exposed through the exposed portion  121 . 
     With the structure in which the lateral side boundary portion  120  includes the exposed portion  121 , it is easy to lower the flexural rigidity of the lateral side boundary portion  120 . Therefore, with such a structure, it is easy to decrease the pronation. 
     Preferably, the lateral first portion L 1 , the lateral bridge  42 , the rear second portion B 2  and the sole  2  define a closed lower area α 1 ; and the exposed portion  121  is placed in the lower area α 1 . 
     With the structure including the lateral side boundary portion  120  where the lower area α 1  includes the exposed portion  121 , it is easy to lower the flexural rigidity of the lower area α 1 . Therefore, with such a structure, it is easy to decrease the pronation. 
     Preferably, the lower area α 1  and the exposed portion  121  are shaped so as to protrude upward. 
     With the structure in which the lower area α 1  and the exposed portion  121  are shaped so as to protrude upward, it is easy to increase the size of the exposed portion  121 . Particularly, it is easy to increase the size of the exposed portion  121  near the lateral side boundary portion  120 . Therefore, with such a structure, it is easy to lower the flexural rigidity of the lateral side boundary portion  120  and decrease the pronation. 
     Preferably, the lateral first portion L 1 , the lateral bridge  42 , the rear first portion B 1  and the rear second portion B 2  define a closed window area α 2 ; and 
     in the window area α 2 , the heel counter  4  defines a rear through hole Bh running through the heel counter  4 . 
     With the heel counter  4  that defines the rear through hole Bh in the window area α 2  on the lateral side, it is easy to lower the flexural rigidity of the upper on the lateral side of the heel portion. Therefore, the pronation will be decreased. 
     Preferably, the reinforcement device  4  includes a heel counter  4  made of a thermoplastic resin; 
     the upper  1  includes an inner skin ( 14 ) placed on a side that comes into contact with a foot, and an outer skin ( 13 ) on an opposite side of the inner skin  14 ; 
     the heel counter  4  is a built-in counter  4  that is built in between the inner skin and the outer skin; and 
     the built-in counter  4  includes the rear first portion B 1 , the rear second portion B 2 , the lateral first portion L 1 , the medial first portion M 1  and the medial second portion M 2 , which are integrally and seamlessly continuous with each other. 
     The built-in heel counter is sandwiched between the inner skin and the outer skin of the upper and functions as the core of the upper, and the built-in heel counter will easily serve as a heel counter despite being thin. 
     Preferably, the built-in counter  4  is plate-shaped as a whole and further includes a low-rigidity portion LW whose rigidity is lower than that of the medial first portion M 1  and the medial second portion M 2 , wherein the low-rigidity portion LW is surrounded by (is bordered on) the rear first portion B 1 , the rear second portion B 2  and the lateral first portion L 1 . 
     In this case, the low-rigidity portion LW on the lateral side, which is a surrounded area, lowers the flexural rigidity of the upper on the lateral side of the heel portion. Therefore, the pronation will be decreased as described above. 
     Preferably, the built-in counter  4  is plate-shaped as a whole and further includes a lateral second portion L 2 , the lateral second portion L 2  being continuous with the rear second portion B 2 , and extending on the lateral side  12  of the upper along the lateral side boundary portion  120  from the rear second portion B 2  toward the anterior direction; 
     the built-in counter  4  includes a lateral central portion LC surrounded by the rear first portion B 1 , the rear second portion B 2 , the lateral first portion L 1  and the lateral second portion L 2 ; and 
     the lateral central portion LC defines a thin portion having a smaller thickness than surrounding portions, one or more slits, or one or more through holes. 
     In this case, the lateral central portion LC forms the low-rigidity portion LW, lowering the flexural rigidity of the upper on the lateral side of the heel portion. Therefore, the pronation will be decreased as described above. 
     Preferably, the built-in counter  4  is plate-shaped as a whole and further includes a lateral second portion L 2 , the lateral second portion L 2  being continuous with the rear second portion B 2 , and extending on the lateral side  12  of the upper along the lateral side boundary portion  120  from the rear second portion B 2  toward the anterior direction; 
     the built-in counter  4  includes a lateral central portion LC surrounded by the rear first portion B 1 , the rear second portion B 2 , the lateral first portion L 1  and the lateral second portion L 2 ; 
     the built-in counter  4  includes a medial central portion MC surrounded by the rear first portion B 1 , the rear second portion B 2 , the medial first portion M 1  and the medial second portion M 2 ; and 
     a thickness of the lateral central portion LC is smaller than a thickness of the medial central portion MC. 
     With the structure in which the thickness of the lateral central portion LC is smaller than the thickness of the medial central portion MC as described above, the flexural rigidity of the lateral central portion LC is lower than the flexural rigidity of the medial central portion MC. Therefore, such a structure will lower the flexural rigidity of the upper on the lateral side of the heel portion and decrease the pronation as described above. 
     Preferably, the built-in counter  4  is plate-shaped as a whole and includes a medial portion  4 M placed on a medial side and a lateral portion  4 L placed on a lateral side, which are seamlessly continuous with each other; and 
     an average thickness of the lateral portion  4 L is smaller than an average thickness of the medial portion  4 M. 
     With the thin structure, the flexural rigidity of the lateral portion  4 L is lower than the flexural rigidity of the medial portion  4 M. Therefore, such a structure will lower the flexural rigidity of the upper on the lateral side of the heel portion and decrease the pronation as described above. 
     Preferably, the lateral central portion LC includes a plurality of through holes arranged in a scattered pattern. 
     The lateral central portion LC having a plurality of through holes forms the low-rigidity portion LW, lowering the flexural rigidity of the upper on the lateral side of the heel portion. Therefore, the pronation will be decreased as described above. 
     Preferably, the lateral central portion LC defines a plurality of slits extending in an anterior-posterior direction. 
     The lateral central portion LC defining a plurality of slits forms the low-rigidity portion LW, lowering the flexural rigidity of the upper on the lateral side of the heel portion. Therefore, the pronation will be decreased as described above. 
     Preferably, the built-in counter  4  is plate-shaped as a whole with a lower edge; and 
     the lower edge is formed in an upward arch shape between the lateral tucked end portion LE and the rear tucked end portion BE. 
     With the structure in which the lower edge of the built-in counter is formed in an upward arch shape on the lateral side, the lateral side boundary portion  120  is more flexurally deformable than the medial side boundary portion  110 . Therefore, the pronation will be decreased as described above. 
     Preferably, the shoe further includes an external counter attached to an outer surface of a rearfoot portion of the upper  1 . 
     When an additional external counter is provided in addition to the built-in counter  4  having the function as described above, it is possible to realize the function-oriented structure of the built-in counter  4  and the design-oriented structure of the external counter. Therefore, it will be advantageous in two ways, i.e., for the function and for the design. 
     Any feature illustrated and/or depicted in conjunction with one of the aforementioned aspects or the following embodiments may be used in the same or similar form in one or more of the other aspects or other embodiments, and/or may be used in combination with, or in place of, any feature of the other aspects or embodiments. 
     EMBODIMENTS 
     The present invention will be understood more clearly from the following description of preferred embodiments taken in conjunction with the accompanying drawings. Note however that the embodiments and the drawings are merely illustrative and should not be taken to define the scope of the present invention. The scope of the present invention shall be defined only by the appended claims. In the accompanying drawings, like reference numerals denote like components throughout the plurality of figures. 
     Embodiments of the present invention will now be described with reference to the drawings. 
     Embodiment 1 
       FIG. 1  to  FIG. 5  show Embodiment 1. 
     General Configuration: 
     As shown in  FIG. 1  to  FIG. 3 , the present athletic shoe includes an upper  1 , a midsole  2 , an outsole  3  and a heel counter (reinforcement device)  4 . 
     As shown in  FIG. 4 , the upper  1  includes a cushioning material  18  made of a foamed resin between a quarter  13  and a quarter lining  14 . Note that the quarter  13  and the quarter lining  14  may be formed from a plurality of layers of fabric. 
     An insole  6  is sewn onto the upper  1 . On the other hand, the upper  1  of  FIG. 1  includes a top line  20  through which the leg extends upward and through which the foot is inserted. 
     The upper  1  includes a fastening means such as a shoelace (not shown). The shoelace fastens the upper  1  so that a medial side  11  of the upper  1  and a lateral side  12  of  FIG. 2  are brought into close contact with the foot in the vicinity of the top line  20 . The reference numeral  16  denotes a tongue provided in front of the top line  20 . 
     The medial side  11  of the upper  1  covers the medial surface of the foot. The lateral side  12  of the upper  1  covers the lateral surface of the foot. A rear end portion  15  of the upper  1  covers the back surface of the foot. The medial side  11 , the lateral side  12  and the rear end portion  15  of the upper  1  together form the top line  20 . 
     In the vicinity of the top line  20  of the upper  1 , the medial side  11  of the upper  1  of  FIG. 1  covers the front end portion B 8   f  of the talus bone B 8  and the front end portion J 8   f  of the subtalar joint J 8 . On the other hand, the lateral side  12  of the upper  1  of  FIG. 2  covers the front end portion B 8   f  of the talus bone B 8  and the front end portion J 8   f  of the subtalar joint J 8 . In the present embodiment, a part of the lateral malleolus Ml and the medial malleolus Mm of  FIG. 1  may each be exposed above the top line  20 . 
     As shown in  FIG. 4A , the heel counter  4  is bonded and secured with no gap to the outer surface of the upper  1  on the medial side  11  and the lateral side  12  of the upper  1 . The upper  1  with the heel counter  4  bonded to the outer surface thereof as described above has a high flexural rigidity and serves to suppress the pronation. 
     The midsole  2  and the outsole  3  of  FIG. 1  are stacked together below the heel counter  4  and the insole  6 . 
     Heel Counter  4 : 
     Next, the heel counter  4 , which is a reinforcement device, will be described. In  FIG. 1  to  FIG. 5 , the heel counter  4  is dotted. 
     The heel counter  4  shown in  FIGS. 1 to 3  is bonded to, and partially exposed on, the outer surface of the fabric of the upper  1  to maintain the shape of a heel portion  17  of the soft upper  1 , which includes a plurality of layers of fabric and is soft. The counter  4  includes the medial portion  4 M placed on the medial side and the lateral portion  4 L placed on the lateral side, which are integrally and seamlessly continuous with each other. 
     The heel counter  4  is formed integrally from a material that includes a thermoplastic resin component. 
     As shown in  FIG. 1  to  FIG. 3 , the medial portion and the lateral portion of the heel counter  4  are formed asymmetric with each other. The heel counter  4  forms a part or whole of the reinforcement device. The heel counter  4  includes a lateral tucked end portion LE, a rear tucked end portion BE and a medial tucked end portion ME to be described later. 
     The heel counter  4  of  FIG. 3  is made of a thermoplastic resin, and includes a rear first portion B 1 , a rear second portion B 2 , a lateral first portion L 1 , a medial first portion M 1  and a medial second portion M 2 , which are formed integrally continuous with each other. The heel counter  4  integrally includes three bridges  40  to  42 , for example. 
     As clearly shown in  FIG. 1  and  FIG. 3 , in the rear end portion  15  of the upper, the rear first portion B 1  is placed between the midsole  2  and the top line  20  of the upper  1 . The second portion B 2  is placed along the boundary portion  10  between the rear end portion  15  of the upper  1  and the midsole  2 . Moreover, the rear second portion B 2  extends to the midsole  2 , and includes the rear tucked end portion BE that is tucked between the midsole  2  and the upper  1 . The bridge  40  on the rear center portion of  FIG. 3  vertically connects between the center of the rear first portion B 1  and the center of the rear second portion B 2 . That is, the bridge  40  is placed directly behind the calcaneal bone B 9  of  FIG. 1 . 
     As shown in  FIG. 1  and  FIG. 2 , the rear end portion  15  of the upper  1  is an extent of 20%, preferably 10%, extending from a rear end  1 E of the upper with respect to the entire length 100% of the upper on the sagittal plane. In the rear end portion  15 , the rear first portion B 1  and the rear second portion B 2  of  FIG. 3  extend in the lateral direction while being curved along the upper. 
     In the rear end portion  15  on the medial side of  FIG. 1 , the medial bridge  41  diagonally connects between the rear first portion B 1  and the rear second portion B 2 . On the other hand, in the rear end portion  15  on the lateral side of  FIG. 2 , the lateral bridge  42  diagonally connects between the rear first portion B 1  and the rear second portion B 2 . A rear through hole Bh, which appears to be a window, may be provided between the three bridges  40  to  42 , as shown in  FIG. 3 . 
     The lateral first portion L 1 , the lateral bridge  42 , the rear first portion B 1  and the rear second portion B 2  define a closed window area α 2 , and the heel counter  4  defines the rear through hole Bh running through the heel counter  4  in the window area α 2 . 
     On the lateral side  12  of  FIG. 2 , the lateral first portion L 1  extends toward the midsole  2  below and toward the diagonal anterior direction reaching the midsole  2 . The heel counter  4  includes the lateral tucked end portion LE that is tucked between the midsole  2  and the upper  1 . 
     The lateral tucked end portion LE is formed by the lateral first portion L 1  extending toward the midsole  2  and toward the anterior direction X 1  reaching the midsole  2  so as to be tucked between the midsole  2  and the upper  1 . 
     On the lateral side  12 , the heel counter  4  is not placed in the lateral side boundary portion  120  of the upper  1 . In the case of the present embodiment, the lateral side boundary portion  120  includes an exposed portion  121  that is exposed and not covered by the heel counter  4 . 
     The lateral first portion L 1 , the lateral bridge  42 , the rear second portion B 2  and the midsole  2  define a closed lower area α 1 , and the exposed portion  121  is placed in the lower area α 1 . 
     Note that the lateral side boundary portion  120  means the vicinity of the boundary between the lateral side  12  of the upper  1  and the midsole  2 . 
     On the medial side  11  of  FIG. 1 , the medial first portion M 1  extends toward the midsole  2  below and toward the diagonal anterior direction reaching the midsole  2 , and is continuous with the medial second portion M 2 . On the medial side  11  of the upper, the medial second portion M 2  extends toward the anterior direction from the rear second portion B 2  along the medial side boundary portion  110  to be continuous with the medial first portion M 1 . 
     A medial through hole Mh, which appears to be a window, may be provided between the medial first portion M 1  and the medial second portion M 2  which are arranged in the vertical direction. 
     Note that the medial side boundary portion  110  means the vicinity of the boundary between the medial side  11  of the upper  1  and the midsole  2 . 
     As shown in the cross sections of  FIG. 4  and  FIG. 5 , the medial tucked end portion ME, which generally is a lower half of the medial second portion M 2 , is tucked between the midsole  2  and the upper  1 . The tucked end portion ME is the medial second portion M 2  tucked between the sole  2  and the upper  1 , and connects together the rear second portion B 2  and the lower end portion of the medial first portion M 1 . On the other hand, an exposed portion M 21 , which generally is an upper half of the medial second portion M 2  of  FIG. 1 , covers the medial side boundary portion  110  of the upper  1  and is exposed. 
     Regarding the flexural deformation that occurs when the upper collapses in the arrow directions of  FIG. 4  and  FIG. 5 , the value of the flexural rigidity ∫EIz of the medial first portion M 1  is greater than the value of the flexural rigidity ∫EIz of the lateral first portion L 1 . In the case of the present embodiment, regarding the flexural deformation, the value of the moment of inertia of area Iz of the medial first portion M 1  is greater than the value of the moment of inertia of area Iz of the lateral first portion L 1 . For example, the thickness of the medial first portion M 1  of  FIG. 5  is greater than the thickness of the lateral first portion L 1 . 
     With such flexural deformation, the moment of inertia of area Iz has such a correlation that it is in proportion to the cube of the thickness. 
     In the case of the present embodiment, the medial first portion M 1  and the lateral first portion L 1  of  FIG. 3  are formed from the same material. Therefore, the medial first portion M 1  and the lateral first portion L 1  have an equal Young&#39;s modulus (longitudinal elastic modulus) E. 
     The medial second portion M 2  is placed on the medial side boundary portion  110  of  FIG. 1 , whereas a member that corresponds to the medial second portion M 2  ( FIG. 1 ) is not placed on the lateral side boundary portion  120  of  FIG. 2 . That is, the medial second portion M 2  is placed on the medial side boundary portion  110  of FIG.  1  so that the medial side boundary portion  110  of  FIG. 1  is less flexural deformable than the lateral side boundary portion  120  of  FIG. 2 . 
     On the medial side  11  of  FIG. 1 , the medial first portion M 1 , the medial second portion M 2  and the bridge  41  are formed to be continuous with each other in a loop shape. The loop-shaped portion increases the average flexural rigidity of the lower portion of the upper from the rear end of the talus bone B 8  to the front end of the lateral malleolus Ml ( FIG. 2 ). The loop-shaped heel counter  4  of  FIG. 1  makes the medial first portion M 1  less flexurally deformable than the lateral first portion L 1  of  FIG. 2 . 
     Next, a test that was conducted to verify the validity of the present invention will be described. For this purpose, first, samples of Types  1  to  5  shown in  FIG. 6  were prepared. 
     The shoe of Type  1  of  FIG. 6  includes a heel counter that has generally the same shape on the medial side and on the lateral side. The lateral side and the medial side of Type  1  have a similar structure to that of the medial side of the heel counter of Embodiment 1. That is, the rigidity of the heel portion of the upper of Type  1  is generally the same on the medial side and on the lateral side. 
     The shoes of Types  2  to  5  were made by partially cutting off the lateral portion and the back portion of the heel counter of Type  1 . Note that the medial portions of the shoes of Types  2  to  5  are similar to those of the heel counter of Type  1 . 
     The heel counter of Type  2  is obtained by being cut off at the lateral side boundary portion  120  ( FIG. 2 ) between the upper of the heel portion lateral side and the midsole  2 . 
     The heel counter of Type  3  is obtained by partially cutting off the lateral side while leaving at the lateral side boundary portion  120  ( FIG. 2 ), the rear first portion and the rear second portion. 
     The heel counter of Type  4  is obtained by cutting off most of the lateral side while leaving the rear first portion and the rear second portion. 
     The heel counter of Type  5  is obtained by cutting off most of the rear first portion and the entire lateral side. 
     The pronation (the heel portion eversion angle ß and the lower leg internal rotation angle γ) and the heel portion holding property (the evaluation value Disp.Z of the foot following property during the latter half of the support period) were measured while actually running. The results are shown in  FIG. 7  to  FIG. 9 . 
     The evaluation value Disp.Z of the following property is the vertical displacement of the foot with respect to the shoe. Therefore, the maximum value of Disp.Z, which is observed during heel rise, is measured as the evaluation value Disp.Zmax, wherein the value being smaller means a better following property and a higher heel portion holding property. 
     It was confirmed that for the heel portion eversion angle ß of  FIG. 7 , Type  2  and Type  5  have smaller absolute values than Type  1 , and for the lower leg internal rotation angle γ of  FIG. 8 , Type  2 , Type  4  and Type  5  have smaller absolute values than Type  1 , i.e., an improvement in the stability property. 
     With the shoe of Type  1  of  FIG. 6 , the heel counter is present in the lateral side boundary portion  120  ( FIG. 2 ) of the heel portion lateral side, where the sole first comes into contact with the ground. 
     In contrast, the samples of Types  2 ,  4  and  5  with an improved stability property described above are obtained by the heel counter being cut off at the lateral side boundary portion  120  ( FIG. 2 ). The low rigidity of the lateral side boundary portion  120  ( FIG. 2 ) increases the deformation of the sole upon landing. It is believed that this suppresses the speed at which the foot collapses toward the medial side and decreases the pronation to be exhibited thereafter. That is, it is believed that the absolute value of the heel portion eversion angle ß of  FIG. 7  and the absolute value of the lower leg internal rotation angle γ of  FIG. 8  are small, thereby improving the stability property. 
     As described above, it can be seen that in order to improve the stability property, it is important to lower the rigidity of the lateral side boundary portion  120  of  FIG. 2 . 
     For the following property of  FIG. 9 , i.e., the heel portion holding property, it can be seen that the evaluation value Disp.Zmax of the following property for Type  3 , Type  4  and Type  5  is increased as compared with Type  1 , thereby resulting in a poor heel portion holding property. 
     With the shoes of Type  3 , Type  4  and Type  5  of  FIG. 6 , most of the heel counter is cut off on the lateral side, thereby lowering the tensile rigidity of the heel portion lateral side. During the dorsiflex phase of the upper, a force that pushes the heel portion of the upper acts in the direction normal to the upper surface, thereby causing a stretch deformation in the area of the heel portion lateral side. It is believed that with the shoes of Type  3 , Type  4  and Type  5 , the heel portion holding property is lowered because the cut-off allows the deformation. 
     Moreover, with the shoe of Type  5 , the counter is cut off not only on the lateral side but also on the back side, thereby lowering the flexural rigidity of an area upon which a force acts directly. It is believed that the heel portion deformation is thus greater as compared with Type  3  and Type  4 , resulting in the lowest heel portion holding property among all the samples. 
     As described above, it can be seen that in order to improve the heel portion holding property, it is important to increase the tensile rigidity of an area that connects together the lateral side and the back portion of the heel portion and the rigidity of the back portion of the heel portion. 
     Next, another test that was conducted to verify the validity of the present invention will be described. For this purpose, samples of Types  21  to  27  shown in  FIG. 14  were prepared. These samples have similar medial sides to those of the samples of  FIG. 6 .  FIG. 14  shows the lateral side of the heel counter. 
     The heel counters of Type  21  of  FIG. 14( a )  and Type  22  of FIG.  14 ( b ) are provided with a lateral through hole Lh that is larger than the medial through hole Mh ( FIG. 1 ). 
     With the sample of Type  21  of  FIG. 14( a ) , the lower end of the lateral through hole Lh is set to be generally at the midsole upper edge  2   e.    
     With the sample of Type  22  of  FIG. 14( b ) , the lower end of the lateral through hole Lh is set to be below the midsole upper edge  2   e.    
     The heel counters of Types  23  and  24  of  FIGS. 14( c ) and 14( d )  have the lateral second portion L 2  that connect together the lateral tucked end portion LE and the rear tucked end portion BE. 
     With the heel counter of Type  23 , the lower end of the lateral second portion L 2  is set to be around the midsole upper edge  2   e.    
     With the heel counter of Type  24 , the lower edge of the lateral second portion L 2  is set to be above the midsole upper edge  2   e.    
     The heel counter of Type  25  of  FIG. 14( e )  is obtained by cutting off about ⅓ of the central portion of the lateral second portion L 2  of the heel counter of Type  21  of  FIG. 14( a ) . 
     The heel counter of Type  26  of  FIG. 14( f )  has a structure obtained by cutting off a rear upper portion on the lateral side of the heel counter of Type  2  of  FIG. 6 . 
     The heel counter of Type  27  of  FIG. 14( g )  has a structure obtained by partially cutting off a rear upper portion and a rear second portion on the lateral side of the heel counter of Type  2  of  FIG. 6 . 
     The heel portion eversion angle ß was measured while actually running. The results are shown in  FIG. 15  and  FIG. 16 . 
     In  FIG. 15 , it can be understood that with Types  21  to  26 , excluding Type  27 , the heel portion eversion angle ß is smaller than Type  1 , as with Type  2 . 
       FIGS. 16( a ) and 16( b )  show the heel portion eversion angle ß for the various samples, wherein the horizontal axis of the graphs represents the cut-off percentage in the vertical direction and the foot longitudinal direction, respectively, of the lateral second portion L 2  ( FIG. 14 ). 
     In the graph of  FIG. 16( a ) , it can be seen that the heel counters of Types  23  and  24 , where even though the lateral second portion L 2  ( FIG. 14 ) is provided, the lateral second portion L 2  is not tucked by the midsole, have generally the same heel portion eversion angle ß as that of the heel counter of Type  2 . That is, also with Types  23  and  24 , the stability property will improve, as with Type  2 . 
     In the graph of  FIG. 16( b ) , it can be seen that from a comparison between Types  25  and  26  and Types  1  and  2 , as the cut-off percentage of the lateral second portion L 2  ( FIG. 14 ) is greater, the absolute value of the heel portion eversion angle ß is smaller, thereby improving the stability property. 
     However, it can be seen that when a large portion of the rear tucked end portion BE ( FIG. 14 ) is cut off, as with Type  27  of  FIG. 16( b ) , the absolute value of the heel portion eversion angle ß will be greater than Type  21 , lowering the stability property. 
     Next, other embodiments will be described. 
       FIG. 10A  and  FIG. 10B  show Embodiment 2. 
     In  FIG. 10A  and  FIG. 10B , the quarter  13  of the upper includes a main member  13   a  and a reinforcement member  13   b . The main member  13   a  is placed over more than a half or most of the quarter  13 , covering the medial side and the lateral side of the foot. The reinforcement member  13   b  is provided in the hatched area of the quarter  13 , for example, and may be stacked on the surface of the main member  13   a  or may be provided by impregnating the main member  13   a  with a resin. 
     The main member  13   a  may be, for example, a mesh material having a lattice structure (mesh structure), a knit fabric, a woven fabric, or the like. These materials are more stretchable than the reinforcement member  13   b.    
     The reinforcement member  13   b  of the medial side  11  of  FIG. 10A  is placed along the medial first portion M 1  of the heel counter  4 . On the other hand, the reinforcement member  13   b  of the lateral side  12  of  FIG. 10B  forms a part of the reinforcement device, and forms the lateral first portion L 1  together with the heel counter  4 . 
     In  FIG. 10B , the reinforcement member  13   b  of the lateral side  12  is placed on the lateral side boundary portion  120 . The reinforcement member  13   b  of the lateral side boundary portion  120  forms the lateral second portion L 2 . Therefore, the lateral side boundary portion  120  has a higher tensile rigidity than a portion where only the main member  13   a  is placed, and has a lower flexural rigidity than the medial side boundary portion  110  of  FIG. 10A . 
     The heel counter  4  of  FIG. 10A  and  FIG. 10B  is not provided with a bridge on the rear center portion. The lateral first portion L 1  of the heel counter  4  extends toward the midsole  2  toward the anterior direction, but does not extend up to the midsole  2 . 
     The width W L  of the lateral first portion L 1  of the heel counter  4  is greater than the width W M  of the medial first portion M 1 . However, the lateral first portion L 1  of the heel counter  4  has a free end on the front side of the rear end portion  15 . Therefore, on the front side of the rear end portion  15 , the lateral first portion L 1  of the heel counter  4  is more flexurally deformable than the medial first portion M 1  of  FIG. 10A . 
     The bridges  41  and  42  of the medial side  11  and the lateral side  12  support the rear first portion B 1 , and therefore the compressive rigidity of the rear end portion  15  of the upper is high. 
       FIG. 11A  and  FIG. 11B  show Embodiment 3. 
     As in the present embodiment, the reinforcement member  13   b  may be provided only on the lateral side  12 . 
     In the present embodiment, the heel counter  4  is formed in a loop shape on the medial side  11  and the lateral side  12 . Also in the present embodiment, the lateral first portion L 1  is formed by the heel counter  4  and the reinforcement member  13   b . The lower portion of the lateral first portion L 1  and the lateral side boundary portion  120  are formed from the reinforcement member  13   b  of the upper, and therefore the lateral first portion L 1  is more flexurally deformable than the medial first portion M 1 . 
       FIG. 12A  to  FIG. 12C  show Embodiment 4. 
     The heel counter  4  of the present embodiment is formed from a tape material. The heel counter  4  of the tape material may be bonded and sewn onto the main member of the quarter  13 . 
     The tape material has a greater Young&#39;s modulus than the main member of the quarter  13 , and is therefore less stretchable and less bendable than the main member. 
     On the heel counter  4  of the present embodiment, the rear second portion B 2  may not be provided on the rear center portion, and may be provided only on the medial side  11  of  FIG. 12A . However, the rear second portion B 2  is provided in the rear end portion  15 , which is a 20% area of the medial side  11  extending from the rear end  1 E. 
       FIG. 13A  and  FIG. 13B  show Embodiment 5. 
     This embodiment is provided with the lateral second portion L 2  that connects together the tucked end portion LE of the lateral first portion L 1  and the rear second portion B 2  of the heel counter  4  of Embodiment 1. The lateral second portion L 2  will slightly reinforce a part of the lateral side boundary portion  120  of  FIG. 2 , and slightly reinforce the midsole  2  directly under the lateral side boundary portion  120 . 
     In this case, it is preferred that the lateral second portion L 2  of the heel counter  4  of  FIG. 13B  is tucked between the upper  1  and the midsole  2  of  FIG. 2  and not exposed to the outside. 
     A part or whole of the heel counter  4  may be exposed on the upper  1  or may be buried in the upper  1 . Where a part or whole of the heel counter  4  is exposed on the upper  1 , it is expected to further improve the stability property and the following property, and is expected to ensure the safety of the upper as a whole. 
       FIG. 17  to  FIG. 21  show Embodiment 6. 
     In  FIG. 17 , the shoe includes the upper  1 , the midsole  2 , the outsole  3  and the heel counter  4 . 
     The upper  1  includes the lateral side boundary portion  120  between the upper  1  and the sole  2  on the lateral side  12  of the upper of  FIG. 18 , the medial side boundary portion  110  between the upper  1  and the sole  2  on the medial side  11  of the upper of  FIG. 17 , and the rear boundary portion  10  between the upper  1  and the sole  2  in the rear end portion  15  of the upper of  FIG. 19 . The medial side boundary portion  110  ( FIG. 17 ) and the lateral side boundary portion  120  ( FIG. 18 ) are continuous with each other with the rear boundary portion  10  interposed therebetween, as shown in  FIG. 19 . 
     The heel counter  4  made of a thermoplastic resin is attached to the outer surface of the upper  1 , as shown in  FIG. 20A  and  FIG. 20B . As shown in  FIG. 21 , the heel counter  4  includes the rear first portion B 1 , the rear second portion B 2 , the lateral first portion L 1 , the medial first portion M 1  and the medial second portion M 2 , which are integrally and seamlessly continuous with each other. 
     The rear first portion B 1  of  FIG. 18  is placed between the sole  2  and the top line  20  of the upper  1 , in the rear end portion  15  of the upper. The rear second portion B 2  is placed in the rear boundary portion  10 . As shown in  FIG. 19 , the rear first portion B 1  and the rear second portion B 2  of the present embodiment are vertically continuous with each other on the back surface of the upper. 
     In the example of  FIG. 18 , the lateral first portion L 1  is continuous with the rear first portion B 1 , and is formed in a strip shape extending on the lateral side  12  of the upper toward the sole  2  and toward the diagonal anterior-downward direction. 
     The medial first portion M 1  of  FIG. 17  is continuous with the rear first portion B 1 , and extends toward the sole  2  on the medial side  11  of the upper. The medial second portion M 2  is continuous with the rear second portion B 2 , and extends on the medial side  11  of the upper along the medial side boundary portion  110  from the rear second portion B 2  toward the anterior direction X 1 . In the case of the present embodiment, the medial first portion M 1 , the medial second portion M 2 , the rear second portion B 2  and the rear first portion B 1  are continuous with each other, with no through holes or cutouts provided therebetween. 
     The lateral first portion L 1  of  FIG. 18  extends toward the sole  2  and toward the anterior direction X 1  reaching the sole  2 , and includes the lateral tucked end portion LE that is tucked between the sole  2  and the upper  1 . The rear end of the lateral tucked end portion LE and the front end of the rear tucked end portion BE are unconnected and separated from each other in the anterior-posterior direction X. That is, in the case of the present embodiment, the lateral tucked end portion LE and the rear tucked end portion BE are continuous with each other by the strip-shaped lateral first portion L 1  and the strip-shaped lateral bridge  42 , but are not continuous with each other below these strip-shaped members. 
     The rear second portion B 2  of  FIG. 19  extends to the sole  2 , and includes the rear tucked end portion BE that is tucked between the sole  2  and the upper  1 . The medial second portion M 2  of  FIG. 17  includes the medial tucked end portion ME that is tucked between the sole  2  and the upper  1  and connects together the rear second portion B 2  and the lower end portion of the medial first portion M 1 . 
     In  FIG. 18 , the heel counter  4  includes the lateral bridge  42  that extends toward the diagonal anterior-upward direction from the rear second portion B 2  to the lateral first portion L 1 . Between the lateral bridge  42  and the lateral first portion L 1  and the sole  2 , the exposed portion  121  is provided where the lateral side boundary portion  120  of the upper  1  is exposed. 
     The lateral first portion L 1 , the lateral bridge  42 , the rear second portion B 2  and the sole  2  of  FIG. 18  define the closed lower area α 1 . The lower area α 1  is formed as a cutout of the heel counter  4 . The exposed portion  121  is placed in the lower area α 1 . The lower area α 1  and the exposed portion  121  are shaped so as to protrude upward. 
     With the structure where the lower area α 1  and the exposed portion  121  are shaped so as to protrude upward, it is easy to lower the flexural rigidity gradually toward the lateral side boundary portion  120 . Therefore, with such a structure, the amount of deformation of the lateral side boundary portion  120  upon heel contact is likely to increase, and it is easy to decrease the pronation. 
     Examples of the structure in which the flexural rigidity lowers gradually toward the lateral side boundary portion include, in addition to the upwardly-protruding exposed portion of the present embodiment, structures where the volume of a low-rigidity portion, such as an exposed portion or a thin portion having a small thickness, increases gradually downward. 
     In  FIG. 18 , the lateral first portion L 1 , the lateral bridge  42 , the rear first portion B 1  and the rear second portion B 2  define the closed window area α 2 . In the window area α 2 , the heel counter  4  defines the rear through hole Bh running through the heel counter  4 . 
     Note that in the case of the present embodiment, the areas α 1  and α 2 , which are through holes, are not provided in the medial portion  4 M of  FIG. 17 . 
     As in the present embodiment, the heel counter  4  may include a projecting portion  49  in the medial portion  4 M of  FIG. 17  and the lateral portion  4 L of  FIG. 18 . The projecting portion  49  extends on the lateral portion  4 L in the diagonal anterior-upward direction from the lateral bridge  42  toward the top line  20  to intersect with the lateral first portion L 1 . 
     The other structures of the present embodiment are similar to those of Embodiment 1 of  FIG. 1  to  FIG. 5  described above, and like members are denoted by like reference signs and will not be further described below. 
       FIG. 22  to  FIG. 26  show Embodiment 7. 
     In the case of the present embodiment, the reinforcement device includes both a built-in heel counter  4  and an external heel counter  400 . 
     The built-in heel counter  4  has a functional feature, and the external heel counter  400  has a design feature. The external heel counter  400  is attached to the outer surface of the rearfoot portion of the upper  1 . 
     As shown in  FIG. 25A  and  FIG. 25B , the upper  1  includes an inner skin  14  placed on the side that comes into contact with the foot, and an outer skin  13  on the opposite side. The built-in heel counter  4  is built in between the inner skin  14  and the outer skin  13 . 
     Note that  FIG. 25A  and  FIG. 25B  are cross sections as seen from the front side of the shoe. In  FIG. 25A  and  FIG. 25B , the midsole  2  of  FIG. 22  and  FIG. 23  is not shown. The built-in heel counter  4  is sandwiched between the upper  1  (the inner skin  14 ) and the midsole  2 . 
     As shown in  FIG. 24 , the built-in counter  4  includes the rear first portion B 1 , the rear second portion B 2 , the lateral first portion L 1 , the medial first portion M 1  and the medial second portion M 2 , which are integrally and seamlessly continuous with each other. 
     As shown in  FIG. 24  and  FIG. 26 , the built-in counter  4  is plate-shaped as a whole and further includes a low-rigidity portion LW whose rigidity is lower than that of the medial first portion M 1  and the medial second portion M 2 , wherein the low-rigidity portion LW is surrounded by the rear first portion B 1 , the rear second portion B 2  and the lateral first portion L 1 . 
     The built-in counter  4  of  FIG. 23  is plate-shaped as a whole and includes the lateral second portion L 2 . The lateral second portion L 2  is continuous with the rear second portion B 2 , and extends on the lateral side  12  of the upper along the lateral side boundary portion  120  from the rear second portion B 2  toward the anterior direction X 1 . 
     The built-in counter  4  includes a lateral central portion LC surrounded by the rear first portion B 1 , the rear second portion B 2 , the lateral first portion L 1  and the lateral second portion L 2 . The lateral central portion LC defines a thin portion having a smaller thickness than the surrounding portions, one or more slits, or one or more through holes. 
     As shown in  FIG. 26( g ) , in the case of the present embodiment, the lateral central portion LC is shown to be a thin portion having a smaller thickness than the surrounding portions. Examples where the lateral central portion LC defines one or more slits or one or more through holes will be described later. 
     As shown in  FIGS. 26( a ) to 26( g ) , the built-in counter  4  includes a medial central portion MC surrounded by the rear first portion B 1 , the rear second portion B 2 , the medial first portion M 1  and the medial second portion M 2 . The built-in counter  4  is plate-shaped as a whole and includes the medial portion  4 M placed on the medial side and the lateral portion  4 L placed on the lateral side, which are seamlessly continuous with each other. 
     The thickness of the lateral central portion LC is smaller than the thickness of the medial central portion MC. In the case of the present embodiment, the average thickness of the lateral portion  4 L is smaller than the average thickness of the medial portion  4 M. For example, the lateral central portion LC of the lateral portion  4 L of  FIGS. 26( c ) and 26( f )  is a thin portion as shown in  FIG. 26( g ) , and the thin portion further includes a plurality of closed grooves extending in the anterior-posterior direction of the foot. Thus, the low-rigidity portion LW is formed. 
       FIG. 27  shows another example of the structure of the lateral portion  4 L of the built-in heel counter  4  of  FIG. 26( c ) . 
     As shown in  FIGS. 27( a ) and 27( d ) , the lateral portion  4 L of the heel counter  4  may include one through hole  4 H or a plurality of through holes  4 H arranged in a scattered pattern provided in the lateral central portion LC. 
     As shown in  FIGS. 27( b ) and 27( c ) , the built-in counter  4  may be plate-shaped as a whole with a lower edge, and the lower edge may be formed in an upward arch shape between the lateral tucked end portion LE and the rear tucked end portion BE. 
     As shown in  FIGS. 27( e ) and 27( f ) , the through holes  4 H may be groove-shaped extending in the anterior-posterior direction in the lateral central portion LC. The grooves may have the same length or different lengths. The direction in which the slits extend may be inclined, and there is no limitation on the direction of inclination. 
     Moreover, the number of groove-shaped through holes  4 H may be one, though it is not shown in the figures. 
     As shown in  FIGS. 27( g ) and 27( h ) , the through holes  4 H may be triangular or polygonal. 
     In the case of  FIGS. 27( a ) to 27( h ) , the through hole  4 H may be a thin portion that is thin and recessed, thereby forming the low-rigidity portion LW. 
       FIG. 28  shows another example of a built-in heel counter. 
     In this example, the heel counter  4  has a flat plate shape, and is built in the rearfoot portion of the upper while being bent along a center line  4 C into a generally U-letter shape. 
     In  FIG. 28 , the counter  4  may include a low-rigidity portion LW formed in the lateral central portion LC by providing a plurality of slits in the lateral central portion LC. The slits may extend in the anterior-posterior direction in the lateral central portion LC. Also in this case, there may be one slit or a plurality of slits. 
     When the built-in heel counter is installed in the upper, no external heel counter may be provided. 
       FIG. 29  shows, together with a part of the upper  1 , another example of an external heel counter  4 . 
     In  FIG. 29 , a thin portion  400  is provided to extend from the rear end of the external heel counter  4  toward the medial side and the lateral side. The distance  40 M from the rear end to the front end of the thin portion  400  in the medial portion  4 M of  FIG. 29( a )  is shorter than the distance  40 L in the lateral portion  4 L of  FIG. 29( b ) . The external heel counter  4  is dotted, and the thin portion  400  are densely dotted. 
     Note that the two-dot-chain line denotes the upper edge line of the midsole. 
     A pattern of small protrusions/depressions may be provided in a portion of the external heel counter  4 . 
     In the present embodiment, the external heel counter  4  is provided with eyelets  401  through which shoelaces are passed. A through hole  402  may be provided in the vicinity of the eyelets  401 . 
     Note that the external heel counter  4  of the present embodiment will allow the upper to be in close contact with the heel. 
       FIG. 30  shows still another example of the external heel counter  4 . 
     In the present embodiment, a bridge  404  forming a through hole  403  is provided to extend from the rear end of the external heel counter  4  to the lateral side and the medial side. In the case of the present embodiment, because of the bridge of the rear end portion, the lateral portion  4 L of  FIG. 30( a )  has a lower rigidity than the medial portion  4 M of  FIG. 30( b ) . 
     While preferred embodiments have been described above with reference to the drawings, various obvious changes and modifications will readily occur to those skilled in the art upon reading the present specification. 
     The sole placed under the upper may include only a so-called “outsole”. 
     When the heel counter is a built-in heel counter, the heel counter may be a thick cardboard or a cardboard impregnated with a resin, as well as a thermoplastic resin. 
     Thus, such changes and modifications are deemed to fall within the scope of the present invention, which is defined by the appended claims. 
     INDUSTRIAL APPLICABILITY 
     The present invention is applicable to athletic shoes such as running shoes and also to various other types of shoes such as walking shoes. 
     REFERENCE SIGNS LIST 
       1 : Upper,  1 E: Rear end,  10 : Boundary portion,  11 : Medial side of upper,  110 : Medial side boundary portion,  12 : Lateral side of upper,  120 : Lateral side boundary portion,  121 : Exposed portion,  13 : Quarter,  14 : Quarter lining,  15 : Rear end portion,  16 : Tongue,  17 : Heel portion,  18 : Cushioning material 
       2 : Midsole,  20 : Top line,  3 : Outsole,  6 : Insole 
       4 : Heel counter (reinforcement device),  40  to  42 : Bridges,  49 : Projecting portion,  4 C: Center line,  4 H: Through hole,  4 L: Lateral portion,  4 M: Medial portion,  400 : External heel counter 
     B 1 : Rear first portion, B 2 : Rear second portion, Bh: Rear through hole, BE: Rear tucked end portion 
     L 1 : Lateral first portion, L 2 : Lateral second portion, LE: Lateral tucked end portion, LC: Lateral central portion 
     LW: Low-rigidity portion 
     M 1 : Medial first portion, M 2 : Medial second portion, M 21 : Exposed portion, MC: Medial central portion, ME: Medial tucked end portion 
     Mh: Medial through hole 
     B 8 : Talus bone, B 9 : Calcaneal bone, J 8 : Subtalar joint 
     Ml: Lateral malleolus, Mm: Medial malleolus 
     α 1 : Lower area, α 2 : Window area, X: Anterior-posterior direction, X 1 : Anterior 
     W L , W M : Width