culottes women's flared trousers cut to look like a skirtBut as far as I know "shorts" are in-between culottes and bloomers, in terms of the length between the bottom rim and the groin. Do you not really distinguish between shorts and bloomers?
What do they wear, then? Off topic, but in Japanese, we call it ブルマ(bloomer). It's not underwears here. The name and the habit of wearing it in PE (though it's almost died out because of hordes of horny men) comes from the eponym, Ms. Bloomer.In the U.S. and Canada men's undergarments can be called shorts but these are not worn by women to play volleyball.