Flatwater racing is also known as sprint canoeing. Race categories vary by the number of athletes in the boat, the length of the course, and whether the boat is a canoe or kayak, with the fastest boat winning the competition. In a kayak, the paddler is seated in the direction of travel, and uses a double-bladed paddle. In a canoe the paddler kneels on one knee with the other leg forward and foot flat on the floor of the boat, and paddles a single-bladed paddle on one side.