How to Teach the Butterfly Kick

Involving the core is critical to learning the dolphin kick

Swimmer doing butterfly stroke
Ezra Shaw/Staff/Getty Images Sport/Getty Images

The butterfly is one of the most difficult swimming strokes. Timing the kicks with the proper leg motion is hard for swimmers to master. But the kick is vital to the stroke and also can be used underwater in a start or a turn. Therefore, a precise method for teaching the butterfly kick is a valuable skill for any coach.

When teaching a swimmer who has never done the butterfly, or dolphin, kick, most of the competitive butterfly kick drills only make learning the butterfly kick more difficult. In some cases, they even promote bad habits. For example, while the kick board is a fabulous tool for learning just about any kick—freestyle, breaststroke, even scissors kick—it doesn't help young butterfly swimmers.

Why? Because it promotes a premature knee bend. While a child is attempting to keep the legs together, performing the fly kick with a kick board makes it nearly impossible for a beginner to get the core involved. An elite swimmer, whose kick has become automatic, can handle it, and it can be useful to work on tightening the abdominal muscles. But it encourages a young swimmer to draw the knees forward, which is a major setback and promotes extreme frontal drag.

Drills Are Important

Other butterfly kicking drills, such as the side body dolphin, vertical dolphin, and back body dolphin, are great ways to practice kicking, but I save them for swimmers who can already do the stroke legally. They are too complex for swimmers just learning how to do the kick.

With beginners, a drill called the body dolphin butterfly kick is a big help. The drill is done in a prone position and swimmers are taught to make the butterfly kick incorporate the entire body, not just the legs. Coaches can use learning cues such as "Kick the head down," "Kick the head up," "bottom down," and "bottom up" because they help young learners get the hang of getting the core involved vs. just kicking from the knees down. It's also helpful to encourage young learners to kick with their legs together, like one big flipper, and even to pretend they are dolphins or mermaids.

The Kick Matters

It's not a good idea to get too detailed when teaching beginning butterfly swimmers, but it's important for teachers and swimmers to understand the action of a good butterfly kick. In a nutshell, the legs are fairly straight during the upward action of the kick and then flex just before the downward action. The legs continue to accelerate kicking downward until they are hyperextended.

Finally, in a swim lesson teaching the body dolphin butterfly kick, discourage your students from ducking their heads. While you want them to kick their heads downward to promote the necessary undulation, a kick that's too deep will slow forward progress and increase frontal drag.