Shoe having an internal chassis

A structural chassis includes a structural chassis and a foam chassis or sock liner sandwiched together to form an assembly that can be inserted into and substantially occupy a footbed of a shoe upper. Discrete sole elements are attached to a bottom side of the upper so as to expose certain portions of the bottom side therebetween. This absence of outsole material in those areas makes the upper collapsible about those areas since the outsole provides no support in those areas. Instead, the structure is provided by the chassis of the chassis, which is customized to the user's foot by placing one or more notches in strategic locations along the chassis where the foot naturally flexes. One such notch is located on the chassis in a position that allows the chassis to flex about a forward push-off axis of the foot that runs through the first and second MTP joints. Two collinear notches are formed on the chassis to allow the structural chassis shoe to flex about a lateral push-off axis that runs through the third, fourth and fifth MTP joints.