It is also possible to use a butterfly kick, although this is rare except after the initial start and after turns. The dolphin kick is essential for many top athletes because it is the fastest part of the race. It may also constitute the majority of the race (i.e., in the 100 yard backstroke the swimmer may kick underwater dolphin for 15 yards per length which equates to as much as 60 yards kicking in a 100 yd race). A great example of this is Olympic gold medallist Natalie Coughlin. Breaststroke kicks are most comfortable if the arms are used synchronized, as the breaststroke kick makes it more difficult to compensate for the rolling movement with alternating arm cycles. The butterfly kick can be done slightly to one side depending on the rolling motion of the body.