Abstract: Support structures for footwear are described including, in one embodiment, one structure in the heel portion of the footwear and another structure in the forefoot portion. One or both of the support structures may be hollow and may include internal support elements such as ridges or posts to support the foot. Additionally, air may be included in the structures with a passageway between the internal support structures permitting the transfer of air back and forth as the wearer treads. Thus, energy is absorbed as the foot strikes the treading surface and is either stored to be returned as the foot rolls forward or, when air is included in the design, is transferred from the heel to forefoot portions and then back again as the foot pressure moves from the heel portion to the forefoot portion.