The butterfly technique is the most modern of all four swimming strokes. Developed from breaststroke, it has similarities as regards undulation and the dolphin type action that occurs. Undulation will occure when the head and upper body rises and falls in realtion to the kick, pull and breathing pattern. Develop a good streamline position by placing your face in the water before the hands enter at the front of the stroke. The hips are swept up to the water surface as the head and face drops down; At this point the arms are being swept forwards over the top of the water with the help of the second leg kick. There are always two leg kicks to every one arm pull within the full stroke cycle. Develop rhythm and timing rather than pure strength and power.