Shoe

Abstract

A shoe having a toe region, a middle region, a heel region, and a multi-layer, multi-density midsole; the midsole being comprised of at least a shank and a lower layer; the bottom surface of the shank having at least one longitudinal concavity and at least one longitudinal convexity, the longitudinal concavity typically occupying a substantial portion of the heel region and the longitudinal convexity typically occupying a portion of the middle region. Collectively, these elements contribute to making the shoe appropriate for both walking and higher impact activities such as running, and simulating the effect, and imparting the fitness benefits, of use on a sandy beach or on a giving or uneven surface regardless of the actual hardness of the surface.

1 . A shoe having an upper, a midsole, and an outsole, wherein said midsole comprises:
 a toe region, a middle region, a heel region, an upper layer, a shank and a lower layer, wherein said shank has a bottom surface, said lower layer has a top surface, said lower layer being located substantially between the outsole and the shank, said shank being located substantially between the lower layer and the upper layer, the bottom surface of said shank substantially facing the top surface of said lower layer, and said upper layer and said lower layer each having a density wherein the density of the upper layer is denser than the density of the lower layer.   
     
     
         2 . The shoe of  claim 1  wherein said bottom surface of said shank has a longitudinal concavity and a longitudinal convexity, wherein said longitudinal concavity occupies a substantial portion of the heel region, and said longitudinal convexity occupies a portion of the middle region. 
     
     
         3 . The shoe of  claim 1  wherein said bottom surface of said shank has a plurality of longitudinal concavities and at least one longitudinal convexity, said plurality of longitudinal concavities comprising at least a first longitudinal concavity and a second longitudinal concavity, wherein said first longitudinal concavity occupies a substantial portion of the heel region and said second longitudinal concavity occupies a portion of the toe region, and said longitudinal convexity occupies a portion of the middle region. 
     
     
         4 . The shoe of  claim 2  wherein said shank has a density greater than said density of the upper layer. 
     
     
         5 . The shoe of  claim 3  wherein said shank has a density greater than said density of the upper layer. 
     
     
         6 . The shoe of  claim 4  wherein said shank contains a cavity in a portion of said middle region. 
     
     
         7 . The shoe of  claim 5  wherein said shank contains a cavity in a portion of said middle region. 
     
     
         8 . The shoe of  claim 4  wherein said shank occupies a substantial portion of the entire length of the midsole. 
     
     
         9 . The shoe of  claim 5  wherein said shank occupies a substantial portion of the entire length of the midsole. 
     
     
         10 . The shoe of  claim 6  wherein said shank occupies a substantial portion of said heel region and a substantial portion of said middle region. 
     
     
         11 . The shoe of  claim 7  wherein said shank occupies a substantial portion of said heel region and a substantial portion of said middle region. 
     
     
         12 . The shoe of  claim 4  wherein said bottom surface of said shank contains a transverse concavity or a transverse convexity. 
     
     
         13 . The shoe of  claim 5  wherein said bottom surface of said shank contains a transverse concavity or a transverse convexity. 
     
     
         14 . A shoe having an upper, a midsole, and an outsole, wherein said midsole comprises:
 a toe region, a middle region, a heel region, a shank and a lower layer, wherein said shank has a bottom surface, said lower layer has a top surface, said lower layer being located substantially between the outsole and the shank, and the bottom surface of said shank substantially facing the top surface of said lower layer.   
     
     
         15 . The shoe of  claim 14  wherein said bottom surface of said shank has a longitudinal concavity and a longitudinal convexity, wherein said longitudinal concavity occupies a substantial portion of the heel region, and said longitudinal convexity occupies a portion of the middle region. 
     
     
         16 . The shoe of  claim 14  wherein said bottom surface of said shank has a plurality of longitudinal concavities and at least one longitudinal convexity, said plurality of longitudinal concavities comprising at least a first longitudinal concavity and a second longitudinal concavity, wherein said first longitudinal concavity occupies a substantial portion of the heel region and said second longitudinal concavity occupies a portion of the toe region, and said longitudinal convexity occupies a portion of the middle region. 
     
     
         17 . The shoe of  claim 15  wherein said shank has a density greater than said density of the lower layer. 
     
     
         18 . The shoe of  claim 16  wherein said shank has a density greater than said density of the lower layer. 
     
     
         19 . The shoe of  claim 17  wherein said shank contains a cavity in a portion of said middle region. 
     
     
         20 . The shoe of  claim 18  wherein said shank contains a cavity in a portion of said middle region. 
     
     
         21 . The shoe of  claim 17  wherein said shank occupies a substantial portion of the entire length of the midsole. 
     
     
         22 . The shoe of  claim 18  wherein said shank occupies a substantial portion of the entire length of the midsole. 
     
     
         23 . The shoe of  claim 19  wherein said shank occupies a substantial portion of said heel region and a substantial portion of said middle region. 
     
     
         24 . The shoe of  claim 20  wherein said shank occupies a substantial portion of said heel region and a substantial portion of said middle region. 
     
     
         25 . The shoe of  claim 17  wherein said bottom surface of said shank contains a transverse concavity or a transverse convexity. 
     
     
         26 . The shoe of  claim 18  wherein said bottom surface of said shank contains a transverse concavity or a transverse convexity.