sentences:  One key to all rolls is that the head comes out of the water last, following the paddler's torso—not first, which presents a non-hydrodynamic profile and tends to oppose the angular momentum which is the hallmark of a successful roll.Thirty-five different types of roll and related maneuvers are performed at the Greenland Kayaking Championships.Different rolls have different purposes, such as righting the kayak if the arms are entangled or injured, if the paddle is lost, if the akuilisaq has come off or is not worn, or if the kayaker has to keep hold of something (in competition, an inflated avataq or an eight-kilogram weight), 
  
  This is the main roll that is usually taught to beginners first and is often what is referred to as "the roll".