Abstract: An outsole having a body member with an inner-structure including a plurality of arcuately shaped ribs extending substantially from the medial to lateral sides thereof. The plurality of arcuately shaped ribs are spaced forwardly, rearwardly, and generally below the metatarsophalangeal joints of a wearer's foot inserted in footwear constructed from the outsole. The inner-structure includes a plurality of sidebars extending forwardly and rearwardly from each of the plurality of arcuately shaped ribs to promote arcuate flexure in front of, behind, and between each of the ribs. The body member includes a peripheral member spaced along the perimeter and connected to the ends of each of the plurality of arcuately shaped ribs, toe and heel support structures configured to reduce flexure in spaces defined between those structures and the peripheral member. The outsole also includes a tread member and a stabilizing member imposed between, and connected to each of, the body member and the tread member.