A method of treating Nitinol to train the structure thereof to remain in the martensite state, including the steps of subjecting the Nitinol to a strain and while subjected to the strain, thermally cycling the Nitinol between a cold bath of about 0.degree. C. to 10.degree. C. and a hot bath of about 100.degree. C. to 180.degree. C. for a minimum of about five cycles.