I don't know if they are shaping up my legs and butt, but they are the most comfortable shoes I own. If you have any back, knee, or ankle problems, you should try a pair of these. I have wide feet but can wear medium width shoes with no problems, and I found all of these sandals true to size. If you are not sure, try on a pair somewhere before you buy them. I found going a size smaller to be too small, according to the directions on the label attached to the shoes. They state, if you find your heel slips at all after 20 or 30 steps then you should go up a size. My heels were right on the edge of the end of the shoe in a size 9, and were within the end comfortably in my normal size 10.