Canoeing is the activity of padling a canoe for the purpose of recreation (also called a float trip), sport, or transportation. It usually refers exclusively to using a paddle to propel a canoe with only human muscle power. A kayak is propelled using a paddle with two blades where the paddler sits with their legs mostly extended in front of them, whereas canoes are propelled using single- or double-bladed paddles where the paddler - a "canoeist" or "canoer"- is kneeling or sitting on seat or thwart, with their knees bent and their legs more or less beneath them. Kayaks are usually closed-decked boats with a spraydeck, while canoes are usually open boats. There are also open kayaks and closed canoes. Technically, a kayak can be seen as a special kind of canoe. When exactly a canoe can be called a kayak is difficult to determine though, and often arbitrary. Internationally, the term canoeing is used as a generic term for both forms though the terms "paddle sports" or "canoe/kayak" are also used. In North America, however, 'canoeing' usually refers only to canoes, as opposed to both canoes and kayaks. Paddling a kayak is also referred to as kayaking.