In one embodiment, the elastic core 36, 136 is made of an elastomeric film or nonwoven elastic or stretchable material including for example block copolymers of polystyrene, polyisoprene or polybutadiene, copolymers of ethylene, natural rubbers, urethanes, kratons, and co-extrusions/blends of the aforementioned material The elastic core can be formed as a membrane or from a plurality of elastic st