Abstract: The present invention relates to an item of footwear comprising a sole with an upper surface having a concave rear portion and a forward portion that is flat in the lateral direction. An item of footwear comprises: a securing means for securing the item of footwear to a foot of a wearer; and a sole having an upper surface that in use contacts the foot of a user, wherein: the upper surface has a first portion (7) and a second portion (6), the first portion (7) located forwardly of the second portion (6); the upper surface is substantially flat in the lateral direction in the first portion (7); and the upper surface is concave in the lateral direction in the second portion (6).