Part I: Don’t Dive Down—Fly Forward!

Welcome to my first ever V.A.Log—aka Video Analysis Blog. With this new series, we are going to dissect different aspects of the Butterfly stroke.

For our first part, we are looking specifically at the undulating motion in fly—why this matters, what you can do to get better with undulating, and common mistakes made within the undulating motion (including an analysis of one of my swimmers)! Be sure to stay tuned throughout the series as it will be action packed!

Let’s get started…

For anyone who has ever been coached with Butterfly—the word undulation should not be new. Undulating means (literally) move like a smooth, wave-like motion. Within our short-axis strokes, undulating is a key component to a faster time. Basically, undulating aids our forward motion in the pool by strengthening our pull (putting us in a stronger physical position to catch water) AND by firing our hips and lower back MORE to create a greater amount of propulsion from our kicks!

Basically–if you do not undulate in fly, you won’t be able to pull or kick as much water!

To have a successful undulation motion during your fly stroke–there are few important concepts:

1.) A Strong Core.

The undulating motion starts at the core and ripples through the body like a wave. Without a strong core to create the motion itself—it will all fall apart and your body alignment will suffer.

2.) What Goes up–Must Come Down!

When teaching kids how to swim fly (especially younger swimmers)–they have tendency to use their undulation to drive themselves up and down, versus (flying) forward. Remember: the goal is to get down the lane as fast as possible—not dive down towards the bottom of the pool. 

3.) Body Alignment is Key!

While swimming fly–if you lead the undulation with your head and not your chest—your body will come out of alignment. This misalignment will create a bigger increase in frontal drag (i.e. more resistance) against your forward motion.

How can I identify if my swimmer is doing those concepts correctly?

Watch my analysis of fly undulation below!


As shown in the video, you can see how that swimmer struggled with the THREE main concepts behind a GREAT undulation. It is imperative (as a coach) that you understand these concepts and can identify these issues within your swimmer stroke’s. I hope–that is why I’m here  .

[CLICK HERE] for Part II—where we will discuss how important the kick is in Butterfly, along with timing issues, and the entire fly sequence!

Until Next Time,

Abbie Fish

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