Abstract: A shock-absorbing midsole component in footwear is disclosed and is made up of spaced upper and lower flexible coextensive layers having a closure strip extending therearound and sealing the layers to form a sealed air space therebetween. A plurality of support ribs extend in spaced relation to each other between the layers and through the interior air space. A one-piece molding process is employed in forming the layers, ribs and common diaphragm of the interior air space. The closure strip is a one-piece element united into an outer peripheral groove formed in surrounding relation to the ribs and diaphragm between the layers.