Dance is considered athletic because most of dances require a lot of physical effort , coordenation and concentration. If you ever tried Zumba or any other type of dance before you know that it is realy hard to focus in memorizing , remembering and performing the dance moves at the same time. And besides that , a lot of dances ( for example Zumba ) can also exercise you and make you produce more energy for being such a good and satifatory activity.
I hope i helped