A weighted shoe insert (1) comprising a weighted base member (3), formed either as an integral portion of a shoe (8) or as a discrete insert sandwiched between an upper adhesively backed cover (2) and a lower adhesively backed cover (4). The base member 3 contains a series of perforations (28) and edge...http://www.google.es/patents/US4709921?utm_source=gb-gplus-sharePatente US4709921 - Weighted insole
