A system for modifying properties of an article of footwear is disclosed, wherein
the article of footwear includes a removable foot-supporting member that includes
a frame portion that defines an aperture, one of a plurality of insert portions
that are received by the aperture, and a restraining member attached to an upper
surface of the frame portion. By removing the insert portion, which has a specific
physical characteristic, and replacing it with an alternate insert portion, which
has a different physical characteristic, properties of the article of footwear
are modified. The restraining member is attached to the upper surface of the frame
portion, but not to the upper surface of the insert portion. The restraining member
prevents upward movement of the insert portions and stretches to accommodate insert
portions having various dimensions.