Patent ID: 7941938

Claim:
An article of footwear comprising, in combination: an upper; a sole assembly secured to the upper and comprising: a first portion having a lower ground engaging surface, an upper surface, and a recess formed in the upper surface, the upper surface of the first portion in contact with the upper; and a second portion seated in the recess in the first portion and having an upper surface, the upper surface of the second portion in contact with the upper, wherein the second portion is formed from a first foam material comprising a reaction product of about 10 to about 100 phr hydrogenated or non-hydrogenated acrylonitrile butadiene copolymer, 0 to about 40 phr modified hydrogenated acrylonitrile butadiene copolymer, and 0 to about 90 phr alpha olefin copolymer, and at least one additive in an amount suitable to form the foam material; wherein the hardness of the first foam material is 25 to 45 Asker C and the density of the first foam material is less than about 0.15 g/cm 3 .