Abstract: Joining a bottom unit, such as an athletic shoe sole, with an upper is achieved with an over molding process. A midsole core may be formed with a direct attach to an underfoot portion of the upper. The forming of the midsole core may be achieved with open cast molding or injection molding, for example. A shell may encapsulate the midsole core and also mechanically engage with the upper to further join the bottom unit with the upper. The shell and the midsole core may be formed from an elastomeric polymer such as polyurethane, thermoplastic polyurethane, ethyl-vinyl acetate, and/or silicone-based materials.