A jumping jack (Canada & US) or star jump (UK and other Commonwealth nations), also called side-straddle hop in the US military, is a physical jumping exercise performed by jumping to a position with the legs spread wide and the hands touching overhead and then returning to a position with the feet together and the arms at the sides. The jumping jack name comes from the traditional toy of the same name, while "star jump" refers to the person's appearance with legs and arms spread.