In some situations canoeing refers to both canoeing and kayaking. Other than by the minimum competition specifications (typically length and width (beam)) and seating arrangement it is difficult to differentiate most competition canoes from the equivalent competition kayaks. The most common difference is that competition kayaks are always seated and paddled with a double-bladed paddle, and competition canoes are generally kneeled and paddled with a single-bladed paddle. Exceptions include Canoe Marathon (in both European and American competitive forms) and sprint (high kneeling position). The most traditional and early canoes did not have seats, the paddlers merely knelt on the bottom of the boat. Recreational canoes and kayaks employ seats and whitewater and surf variants employ the use of foam 'saddles' with thigh straps or increasingly foam 'bulkheads' with integrated thigh hooks that give greater boat control under extreme conditions.