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by Andrew Sheaff

May 24, 2022

Breaking underwater kicking into its critical components

The first article in this series, The Three Ways to Swim Faster, outlined the three requirements for fast swimming: increased propulsion, reduced resistance, and great timing. The major components of successful underwater kicking are:

  1. Maintain a stable platform
  2. Create as much propulsion as possible
  3. Maintain equal propulsion and tempo in both directions
  4. Maintain a posture that reduces drag

Maintain a stable platform

To effectively undulate, swimmers must establish a stable platform at the top of the body, starting with the hands and head.

Pretend your hands are in cement

You’ll see novice underwater dolphin kickers moving their hands all over the place. While they’re attempting to create undulation, they’re ensuring that undulation won’t happen where it matters. If you want to undulate the torso, there needs to be stability in the upper body. Pretend your hands are locked into concrete, and they’re rock solid. Don’t let them move.

Undulate following stability

Once you can keep you head and hands locked in, then you can experiment with more and more undulation of the hips and the kick. This will only be effective if you can create a source of stability by keeping the hands and head still.

Although there are elite underwater dolphin kickers who have some hand motion, they’re executing an advanced version of dolphin kicking that’s only possible when the basics are ironclad.

Create as much propulsion as possible

Underwater swimming is no different than surface swimming. You need to hold water for as long as possible to create speed. With underwater dolphin kicking, you need to make sure you’re accomplishing this task in both directions.

Create pressure

Create as much pressure on your shins and feet as possible. More pressure means you’re holding more water. Holding more water means more speed. As much as possible, make sure your feet are facing backward to move you forward.

Kick fast

Dolphin kick is not a cautious action. It should be fast and aggressive. If you want to go fast, you need to kick hard. The goal is not to see how far you can go with each kick. The goal is to see how fast you can go, and that requires foot speed. It’s probably faster than you think it is.

Kick through the center line

Although kicking fast is critical, the kicks need to be full for the speed to be effective. A key skill in dolphin kicking is kicking through the center line. When you kick from back to front, your feet should end up in front of your body. Many swimmers only manage to kick back to the center, or directly under their hip and in line with their body. Focus on kicking all the way through the center line to get as much as possible out of each kick. If you can execute this skill fast, you’ll be a force to reckon with underwater.

Maintain equal propulsion and tempo in both directions

The human knee is a wonderful joint, but it isn’t designed for dolphin kicking. Fish can easily create propulsion equally in both directions, humans not so much. The forward kick, with the leg moving from behind the body to the front, is more effective than when the legs are moving backward. Faster underwater dolphin kickers, however, tend to have more symmetrical kicks than slower underwater dolphin kickers. If you want to get better underwater, you need to be more symmetrical.

Keep it straight

Many swimmers bend their knees too much, especially when kicking backward. Try to keep your legs straight during the back kick. That’s how it should feel, even though they won’t be straight. For most swimmers, this backward kick will feel very stiff, but it’s effective and does a great job of setting up the next forward kick.

Exaggerate foot speed

Elite kickers maintain higher foot speed while kicking back behind the body. To improve your underwaters, keep your foot speed high in both directions. As the forward kick tends to take care of itself, put your emphasis on exaggerating the foot speed in the opposite direction. You’ll probably need to force it at first.

Maintain a posture that reduces drag

As the body is completely submerged while underwater dolphin kicking, alignment becomes a critical factor in how fast you go. The more aligned you are underwater, the less propulsion you’ll have to create to achieve a certain speed. Most swimmers pay more attention to how they’re kicking as opposed to shaping the vessel that the kick is propelling.

Control your undulation

Great dolphin kicking isn’t all about undulation. Although more undulation is going to create more propulsion, it’s going to create even more drag. Some undulation is required to get a good kick. More is not better, however. Keep it relatively controlled.

Keep the spine straight

Regardless of how much you undulate, your spine should be relatively straight. You don’t see too many submarines with a giant kink in the middle. The straighter the vessel, the faster you’ll go. Try to keep everything straight from head to toe, with only your undulation and kicking actions moving off that straight line.

Putting it all together

Although underwater dolphin kicking is the new kid on the block, it’s here to stay. Swimmers are kicking underwater faster than they can swim in all three strokes that permit it. For swimmers looking to continue to improve, getting better at underwater kicking isn’t optional. For those new to underwater travel, it can be difficult to know where to start. Keep it simple. Follow the simple tasks outlined here, focusing on one or two of them at a time. With practice, you’ll find yourself swimming faster and faster underwater.

See all the articles in this series:

Swimming Technique: Breaking swimming into its critical components
Butterfly Technique: Breaking butterfly into its critical components
Backstroke Technique: Breaking backstroke into its critical components
Breaststroke Technique: Breaking breaststroke into its critical components
Freestyle Technique: Breaking freestyle into its critical components


  • Technique and Training


  • Kicking