Underwater Kick Propulsion: The Complete Guide

How the Underwater Dolphin Kick Creates Speed

Although creating as little resistance as possible is important for doing fast underwater dolphin kick, you also have to create propulsion to move forward. Even with the best alignment in the world, no propulsion still equals no speed.

How do you create a lot of propulsion? You have to push backward against the water as much as you can with your legs, particularly your feet. There are three ways to move more water:

1. Get as much surface area facing backward as possible. The more you can get your feet and shins facing backward as you kick, the better. The more you can do so, the more you can push backward against the water. Think about why fins are so effective. They artificially allow you to create more surface area. Furthermore, the flexibility of the fin allows you to get more of that surface area facing backward. The more you can accomplish both goals with your feet, the better.
2. Use an effective kick over as large a range of motion as possible. If you’re creating an effective surface area for kicking, and you’re able to hold that surface area for a larger range of motion, that means you’re able to push backward more against the water with each kick. That means more speed. It’s important to note that the bigger range of motion is only effective if you can continue to move water backward throughout your kick.
3. Accelerate through your kick to create more propulsion. The more you can accelerate through your kick, the more pressure you can create to push backward against the water.

The Importance of the Down-Kick to the Underwater Dolphin Kick

The down-kick is responsible for most of the propulsion you create during underwater dolphin kick. If you’re a backstroker, switch this term to up-kick. The more effective your down-kick is, the more propulsion you create and the faster you swim. The down-kick is the movement during which your leg travels from behind your body and ends in front your body. When working to create more propulsion, focus on your down-kick.

A great down-kick starts with the wave of undulation initiated from your stable upper body. As the wave travels down your body, it gets bigger and faster. Your hips move forward, then your thighs, then your shins, then your feet. At each step of the process, there’s more range of motion and more speed. This ultimately leads to a whip-like snapping action during which your feet are used to create propulsion.

A key skill for optimizing your down-kick is to execute a skill known as “kicking through the center line.” This means that you want to focus on kicking well in front of your torso. This optimizes the range of motion that you kick with while also controlling your torso range of motion. It ensures that you’re moving through a bigger range of motion with your legs than with your body. This helps you optimize the trade-off between creating a lot of resistance and creating a lot of propulsion. Learn this skill by doing targeted drills that help you feel effective positions.

When performing these skills, the more you can keep pressure on the water with the tops of your feet, and the more that pressure can be directed backward, the more propulsion you’ll be able to create. Just as you can “hold” water with your arms, you can do the same with your feet. Doing so is a critical component of underwater kick.

The Importance of the Up-Kick to the Underwater Dolphin Kick

Although the down-kick gets most of the focus because of its role in creating propulsion, the up-kick is just as important. In fact, the up-kick, not the down-kick has been consistently shown to be related to faster underwater dolphin kick in research.

Your up-kick is the recovery of your underwater kick while you’re on your front. Just switch the terms up-kick and down-kick here if you’re doing backstroke. It happens when your legs move from in front of your body to the back of your body. By repositioning your legs quickly and effectively, you can initiate your next down-kick.

The most important thing for a great up-kick is that it’s fast. Too many swimmers are slow and patient with their up-kick. Don’t do that. Be as fast as possible with your up-kick. A faster up-kick has been shown to be related to fast underwater kick. It’s one of the only factors that has been repeatedly linked to fast underwater kick.

How your legs are repositioned during your up-kick matters as well. Although you should have a bend in your knee during your down-kick, your leg should be moved straight up during your up-kick, with no bend. This is important because by lifting your leg straight up, it can then be snapped back down with a lot of force. The straight recovery allows for the whip-like action of the down-kick, which creates propulsion.

There’s evidence that some swimmers generate propulsion during the up-kick and that the reversal point at which your up-kick transitions to your down-kick can generate propulsion as well. Doing a great up-kick will help you maximize the impact of your up-kick.

Common Propulsion Mistakes in Underwater Dolphin Kick

The most common mistakes swimmers make when trying to create propulsion while doing underwater dolphin kick relate to being unable to do an execute effective down-kick and up-kick:

1. Failing to kick through your center line. If you can kick properly, you’ll go through the full range of motion available to you. Your feet are a lot less effective at creating propulsion than your hands, so if you limit your range of motion, you’re further limiting the amount of propulsion you can create with your feet. Going through an effective range of motion will generate more speed.
2. Failing to maintain foot speed during your kicks. Make sure that you’re kicking fast in both directions, your up-kick and your down-kick. Some swimmers do a good job going fast with their down-kick, but most fail to go fast during their up-kick. Keep your foot speed up in both directions, so that you can create a lot of propulsion during your down-kick and then quickly recover your legs to prepare for your next down-kick.
3. Failing to recover your legs straight during your up-kick. Bending your knees during your up-kick (or down-kick while doing backstroke) has two negative consequences. First, you aren’t positioning your legs for an effective down-kick, which reduces propulsion. Second, you’re moving your shin against the flow of the water. It’s like putting on the brakes.

These common mistakes all lead to a lack of propulsion. If you can avoid these mistakes, you’re much more likely to create speed underwater.

Breaststroke Pull-Out

Although the breaststroke pull-out hasn’t always been associated with underwater dolphin kick, when the single dolphin kick became legal during the pull-out in 2005, that all changed. Now it’s an important component of a great pull-out. Although you can only do one underwater dolphin kick during each pull-out, the same principles apply in creating as much propulsion as possible.

A great underwater dolphin kick starts with a straight up-kick. Although your up-kick doesn’t need to be as fast because it’s only one kick, you want to recover your legs straight to set up an effective down-kick that can be used to create a lot of propulsion. Do the same whip-like motion with your down-kick when your whole leg snaps down. Your legs will typically kick through the center line in underwater kick, and then you’ll quickly recover the leg straight up to bring it back into line with your body. It’s the same basic motion as during underwater kick except that you’ll do one violent kick as opposed to a series of rhythmic kicks.

The timing of your underwater dolphin kick is important as well. You can do it just prior to initiating your pull-out or you can do it at the end of your pull-out as your hands finish their stroke to your sides. Both strategies can be effective at enhancing your pull-out.

Elite swimmers tend to do their underwater dolphin kick before the pull-out. If you’re not doing your underwater dolphin kick at that time, explore whether it’s more effective for you to do so. Ultimately, you’ll want to see which kick timing is consistently faster and then commit to training and competing with the more effective strategy.

How to Improve Your Breath Control

There are three demands you have to manage to consistently do fast underwater dolphin kick in races:

1. Develop the skill and speed of your underwater kick. If you can’t do it fast, nothing else matters.
2. Repeatedly create speed with your underwater kick. If you can’t create speed over and over again, you won’t be able to do so in a race.
3. Do great kicks with tired legs while you’re running out of air.

All three areas can be trained. The first two are straightforward. Work the key skills and then perform them in more difficult situations. Breath control requires a different approach. You don’t need to and shouldn’t do anything dangerous to improve this skill. It’s not safe or effective. Instead, taking simple approaches can make all the difference.

A large part of your underwater kick work must take place underwater. By being underwater, you’re improving your breath control. By simply doing the same basic underwater kick drills and sets and slowly increasing the distances and reducing the rest periods over time, you’ll develop the fitness to hold your breath.

The simplest and most straightforward strategy for developing the breath control you need to do great underwater kicks is to commit to a certain number of kicks during every length of every set. At first, just one kick may be challenging. Once you’re more comfortable, add a second kick. Continue this patient progression over time until you can consistently perform the desired number of kicks.

Although not specific to underwater kick, restricted breathing patterns while swimming can be helpful. Again, start with what’s comfortable and slowly increase the challenge over time for optimal results.