The main blades are ordinarily around 4 millimetres thick, although they can vary depending on the shoe size of the athlete. They also curve round to one side in order to assist with turns on the ice. Athletes will always attempt to skate on the very edges of the figure skate blades. For ice dancing, athletes usually have slightly shorter blades on the base of their shoes, with slightly different design to accommodate step-work rather than jumping. Men and women are required to wear specific costumes in order to perform on the professional stage. Men are asked to wear trousers, whilst women are required to wear tights, trousers, or unitards, as well as skirts.