Articles of Footwear

Abstract

An article of footwear including a footwear upper and a sole assembly secured to the footwear upper. The sole assembly has a forefoot portion and a heel portion, and includes an outsole, a midsole disposed on the outsole and an instability insert disposed between the outsole and the midsole in the forefoot portion of the sole assembly. The instability insert causes a forefoot protrusion to be defined by the outsole in the forefoot portion of the sole assembly.

1 . An article of footwear comprising:
 a footwear upper; and   a sole assembly secured to the footwear upper, the sole assembly comprising an outsole defining a substantially convex instability protrusion;   wherein the instability protrusion defines a radius of curvature of between about 130 mm and about 190 mm; and   wherein the instability protrusion has a length along the outsole of between about 65 mm and about 85 mm, a width along the outsole of between about 45 mm and about 55 mm, and a height, measured from a lowest point of the protrusion to an outer edge of the outsole, of between about 4 mm and about 12 mm.   
     
     
         2 . The article of footwear of  claim 1 , wherein the instability protrusion defines a substantially elliptical shape having a length along the outsole of about 76 mm and a width along the outsole of about 50 mm. 
     
     
         3 . The article of footwear of  claim 1 , wherein a longitudinal axis of the instability protrusion is arranged at an angle of between about 10° and about 30° with a transverse axis of the sole assembly. 
     
     
         4 . The article of footwear of  claim 3 , wherein the longitudinal axis of the instability protrusion is arranged at an angle of about 20° with the transverse axis of the sole assembly. 
     
     
         5 . The article of footwear of  claim 1 , wherein the instability protrusion defines a radius of curvature of about 160 mm. 
     
     
         6 . The article of footwear of  claim 1 , wherein the instability protrusion has a height, measured from a lowest point of the protrusion to an outer edge of the outsole, of about 8 mm. 
     
     
         7 . The article of footwear of  claim 1 , wherein the sole assembly further comprises:
 a midsole disposed on the outsole; and   an instability insert disposed between the outsole and the midsole in the forefoot portion of the sole assembly, the instability insert defining the instability protrusion extending from the outsole in the forefoot portion of the sole assembly.   
     
     
         8 . The article of footwear of  claim 7 , wherein the instability insert defines a substantially elliptical shape in top and side views. 
     
     
         9 . The article of footwear of  claim 8 , wherein the instability insert has a thickness of between about 3 mm and about 9 mm, a length of between about 65 mm and about 85 mm, and a width of between about 45 mm and about 55 mm. 
     
     
         10 . The article of footwear of  claim 7 , wherein the instability insert comprises polyurethane. 
     
     
         11 . The article of footwear of  claim 7 , wherein the instability insert has a durometer of between about 15 Asker C and about 20 Asker C. 
     
     
         12 . The article of footwear of  claim 1 , wherein the sole assembly further comprises:
 a midsole disposed on the outsole; and   a heel insert disposed substantially between the outsole and the midsole in a heel portion of the sole assembly, the heel insert configured to collapse under the weight of a user.   
     
     
         13 . The article of footwear of  claim 12 , wherein the heel insert comprises at least one of polyurethane and a ethylene-vinyl-acetate copolymer (EVA). 
     
     
         14 . The article of footwear of  claim 12 , wherein the heel insert has a durometer of between about 42 Asker C and about 48 Asker C. 
     
     
         15 . The article of footwear of  claim 12 , wherein the heel insert has a thickness of between about 10 mm and about 35 mm. 
     
     
         16 . An article of footwear comprising:
 a footwear upper; and   a sole assembly secured to the footwear upper, a forefoot portion of the sole assembly defining a substantially convex instability protrusion, the instability protrusion providing a first period of instability upon receiving the weight of a user followed by a second period of stability after at least partially collapsing the instability protrusion under the weight of the user;   wherein the instability protrusion has a length along the sole assembly of between about 65 mm and about 85 mm and a width along the sole assembly of between about 45 mm and about 55 mm.   
     
     
         17 . The article of footwear of  claim 16 , wherein the instability protrusion defines a substantially elliptical shape having a length along the sole assembly of about 76 mm and a width along the sole assembly of about 50 mm. 
     
     
         18 . The article of footwear of  claim 16 , wherein the instability protrusion has a height, measured from a lowest point of the protrusion to an outer edge of the sole assembly, of between about 4 mm and about 12 mm. 
     
     
         19 . The article of footwear of  claim 16 , wherein the instability protrusion defines a radius of curvature of between about 130 mm and about 190 mm at least along a transverse axis of the sole assembly. 
     
     
         20 . The article of footwear of  claim 16 , wherein a longitudinal axis of the instability protrusion is arranged at an angle of between about 10° and about 30° with a transverse axis of the sole assembly. 
     
     
         21 . The article of footwear of  claim 16 , wherein the sole assembly further comprises:
 an outsole;   a midsole disposed on the outsole; and   an instability insert disposed between the outsole and the midsole in a forefoot portion of the sole assembly, the instability insert defining the instability protrusion extending from the outsole.   
     
     
         22 . The article of footwear of  claim 21 , wherein the instability insert defines a substantially elliptical shape in top and side views. 
     
     
         23 . The article of footwear of  claim 22 , wherein the instability insert has a thickness of between about 3 mm and about 9 mm, a length of between about 65 mm and about 85 mm, and a width of between about 45 mm and about 55 mm. 
     
     
         24 . The article of footwear of  claim 21 , wherein the instability insert comprises polyurethane. 
     
     
         25 . The article of footwear of  claim 21 , wherein the instability insert has a durometer of between about 15 Asker C and about 20 Asker C. 
     
     
         26 . The article of footwear of  claim 16 , wherein the heel portion is configured to at least partially collapse upon receiving the weight of a user and cause the user to rotate the sole assembly forward, placing the weight of the user on the forefoot portion of the sole assembly. 
     
     
         27 . The article of footwear of  claim 26 , wherein the sole assembly further comprises:
 an outsole;   a midsole disposed on the outsole; and   a heel insert disposed substantially between the outsole and the midsole in a heel portion of the sole assembly, the heel insert configured to collapse under the weight of a user.   
     
     
         28 . The article of footwear of  claim 27 , wherein the heel insert comprises at least one of polyurethane and a ethylene-vinyl-acetate copolymer (EVA). 
     
     
         29 . The article of footwear of  claim 27 , wherein the heel insert has a durometer of between about 42 Asker C and about 48 Asker C. 
     
     
         30 . The article of footwear of  claim 27 , wherein the heel insert has a thickness of between about 10 mm and about 35 mm. 
     
     
         31 . An article of footwear comprising:
 a footwear upper; and   a sole assembly secured to the footwear upper, the sole assembly comprising:
 a forefoot portion of the sole assembly defining a substantially convex instability protrusion, the instability protrusion providing a first period of instability upon receiving the weight of a user followed by a second period of stability after at least partially collapsing the instability protrusion under the weight of the user; and 
 a heel portion configured to at least partially collapse upon receiving the weight of a user and cause the user to rotate the sole assembly forward, placing the weight of the user on the forefoot portion of the sole assembly. 
   
     
     
         32 . The article of footwear of  claim 31 , wherein the instability protrusion has a length along the sole assembly of between about 65 mm and about 85 mm and a width along the sole assembly of between about 45 mm and about 55 mm. 
     
     
         33 . The article of footwear of  claim 32 , wherein the instability protrusion defines a substantially elliptical shape having a length along the sole assembly of about 76 mm and a width along the sole assembly of about 50 mm. 
     
     
         34 . The article of footwear of  claim 31 , wherein the instability protrusion has a height, measured from a lowest point of the protrusion to an outer edge of the sole assembly, of between about 4 mm and about 12 mm. 
     
     
         35 . The article of footwear of  claim 31 , wherein the instability protrusion defines a radius of curvature of between about 130 mm and about 190 mm at least along a transverse axis of the sole assembly. 
     
     
         36 . The article of footwear of  claim 31 , wherein a longitudinal axis of the instability protrusion is arranged at an angle of between about 10° and about 30° with a transverse axis of the sole assembly. 
     
     
         37 . The article of footwear of  claim 31 , wherein the sole assembly further comprises:
 an outsole;   a midsole disposed on the outsole; and   an instability insert disposed between the outsole and the midsole in a forefoot portion of the sole assembly, the instability insert defining the instability protrusion extending from the outsole.   
     
     
         38 . The article of footwear of  claim 37 , wherein the instability insert defines a substantially elliptical shape in top and side views. 
     
     
         39 . The article of footwear of  claim 38 , wherein the instability insert has a thickness of between about 3 mm and about 9 mm, a length of between about 65 mm and about 85 mm, and a width of between about 45 mm and about 55 mm. 
     
     
         40 . The article of footwear of  claim 37 , wherein the instability insert comprises polyurethane. 
     
     
         41 . The article of footwear of  claim 37 , wherein the instability insert has a durometer of between about 15 Asker C and about 20 Asker C. 
     
     
         42 . The article of footwear of  claim 41 , wherein the sole assembly further comprises:
 an outsole;   a midsole disposed on the outsole; and   a heel insert disposed substantially between the outsole and the midsole in a heel portion of the sole assembly, the heel insert configured to collapse under the weight of a user.   
     
     
         43 . The article of footwear of  claim 42 , wherein the heel insert comprises at least one of polyurethane and a ethylene-vinyl-acetate copolymer (EVA). 
     
     
         44 . The article of footwear of  claim 42 , wherein the heel insert has a durometer of between about 42 Asker C and about 48 Asker C. 
     
     
         45 . The article of footwear of  claim 42 , wherein the heel insert has a thickness of between about 10 mm and about 35 mm.