When exercising, wear sturdy and supportive shoes that are not worn out, preferably athletic shoes. To check if your shoes are too worn, place your shoes on a table or counter at eye level and determine if the soles are worn on the outside or inside edges. You may see wear in the soles on either side and/or in the heel of the shoe, leaning in or out. Exercising with shoes that are worn out can overstress the joints. As a rule of thumb: if you have been using one pair of athletic shoes for a year, it is time to replace them.
(Source: Nelson, et. al. Strong Women and Men Beat Arthritis. G.P Putnam’s Sons. New York: 2002)