Article of footwear

There is disclosed an article of footwear having an upper and a sole structure secured to the upper, the sole structure comprising a plurality of sole elements extending downward from a connecting portion, the sole elements being separated by a plurality of sipes that extend upward into the sole structure, the plurality of sipes including: a first sipe oriented in a longitudinal direction with respect to the footwear, the first sipe extending through forefoot, midfoot and heel regions of the sole structure, and the first sipe being positioned closer to a lateral side of the footwear than a medial side of the footwear in the forefoot region; a second sipe that extends in the longitudinal direction, the second sipe extending through only the forefoot region of the sole structure; and a plurality of third sipes extending laterally and substantially straightly between a medial side of the footwear and a lateral side of the footwear, wherein a first portion of the third sipes is positioned in the forefoot region and a second portion of the third sipes is positioned in the heel region, the first portion of the third sipes extending in directions non-parallel to directions at which the second portion of the third sipes extend, and wherein the connecting portion and the sole elements are formed of unitary construction from a polymer foam material, and a thickness of the connecting portion varies between the forefoot region and the heel region.