Master the Underwater Dolphin Kick: Technique Drills for Faster Turns

Why the Underwater Dolphin Kick Wins Races

The underwater dolphin kick is the closest a swimmer gets to flying. In the 50-meter freestyle, Olympic-level men spend up to 15 meters underwater off each wall, and their split times underwater are often faster than their surface swimming. According to a 2016 study in the Journal of Strength and Conditioning Research, elite swimmers achieve velocities of 2.2 to 2.6 meters per second during the underwater phase, compared to about 1.9 meters per second on the surface. That difference is the race.

For age-group and Masters swimmers, the dolphin kick is often the most underdeveloped skill. Most swimmers kick with a straight body, but the key is a wave that starts in the chest, travels through the hips, and finishes with a sharp snap of the feet. This article breaks down the technique into its components and provides six drills you can do at your next practice to build a faster, more efficient underwater game.

Body Position: The Core of the Kick

The first mistake swimmers make is bending at the knees. A proper dolphin kick is a full-body undulation, not a knee-driven flutter. Your body should form a long, torpedo-like line from fingertips to toes. Keep your head in a neutral position, looking directly down at the bottom of the pool. Your chin should be tucked slightly, but not so much that you break the line of your neck.

Think of your torso as a stiff board that rocks from side to side. The wave begins with a slight depression of your chest, then your hips rise, and finally your feet snap downward. This sequence is what propels you forward. If you kick from your knees, you create drag and waste energy. A good mental cue is to imagine you are trying to press your belly button toward the bottom of the pool on each upward kick.

The Role of the Core

Your abdominal and lower-back muscles are the engine. They initiate the undulation and transfer power to your legs. A strong core also prevents your hips from sinking, which is the most common drag problem. If your hips drop, your legs follow, and you create a massive frontal surface area. To test your core engagement, try a vertical dolphin kick in deep water. If you can maintain the kick for 30 seconds without your head going underwater, your core is doing its job.

Kick Timing: The Downbeat Is Everything

In the dolphin kick, the downbeat (when your feet move downward) is the propulsive phase. The upbeat is a recovery. Many swimmers try to kick both ways with equal force, which is inefficient. Focus on a powerful, explosive downbeat, followed by a relaxed, quick recovery upward. The frequency of your kick should be fast, but not frantic. Elite swimmers kick at a rate of about 2.5 to 3 cycles per second, but that rate comes from hip speed, not knee flailing.

To improve timing, practice the kick on your side. Lie on your side with one arm extended overhead and the other along your side. Kick with your body in a straight line, and you will feel the downbeat naturally. This drill also helps you isolate the kick and build body awareness.

Breath Control: The Hidden Limiter

Underwater dolphin kicks are anaerobic. You are holding your breath while exerting maximum effort, which causes a rapid buildup of carbon dioxide. To extend your underwater distance, you must learn to manage your breath and relax your neck and shoulders. Take a full, deep breath before you push off, and then exhale slowly through your nose as you kick. This prevents the feeling of air hunger and keeps your body relaxed.

A common mistake is to hold your breath with a closed glottis, which increases pressure in your chest and can cause your head to rise. Instead, let a small stream of bubbles escape continuously. This also helps you maintain a neutral head position. Practice this by doing 15-meter underwater kicks with a snorkel, focusing on a slow, steady exhale.

Six Drills to Build a Faster Dolphin Kick

Here are six drills you can incorporate into your warm-up or main set. Do each for 4 x 25 meters, with 20 seconds rest, and focus on quality over speed.

1. Vertical Dolphin Kick: In deep water, cross your arms over your chest and kick vertically, trying to keep your head above the surface. This builds core strength and kick power. Do 10 seconds on, 10 seconds off for 5 rounds.
2. Side Kick with Streamline: Lie on your side, bottom arm extended overhead, top arm at your side. Kick for 25 meters, then switch sides. This isolates the downbeat and improves hip rotation.
3. Underwater Kick with Fins: Use short fins (like Zoomers) and do a 25-meter underwater kick, focusing on a tight streamline and fast, compact kicks. Fins exaggerate the downbeat and build ankle flexibility.
4. Kick on Back with Hands at Sides: Lie on your back, arms at your sides, and do a dolphin kick. This removes the streamline and forces you to use your core to keep your hips up. It also helps you feel the wave from your chest.
5. Underwater Kick with a Board: Hold a kickboard vertically in front of you, with your hands on the top edge, and push it through the water as you kick. This adds resistance and forces you to keep your body long.
6. Breakout Kick: From a push-off, do five dolphin kicks, then break out into freestyle. Count your kicks and try to reach the same distance with fewer kicks each set. This teaches you to maximize distance per kick.

Common Mistakes and Fixes

Even with good technique, swimmers make mistakes that slow them down. One is kicking too deeply. The amplitude of your kick should be about 12 to 18 inches (30–45 cm) from the peak of the upbeat to the bottom of the downbeat. Any deeper and you create drag; any shallower and you lose power.

Another mistake is rushing the kick. Swimmers often try to kick as fast as possible, but the fastest kick is not always the fastest swim. A long, powerful downbeat with a quick, relaxed recovery is more efficient. Use a tempo trainer to find your optimal kick rate. Set it at 1.2 seconds per cycle and adjust from there.

Comparing the Dolphin Kick to Other Underwater Kicks

While the dolphin kick is the fastest underwater technique for most strokes, some swimmers experiment with a flutter kick or a breaststroke pullout. The table below compares the three:

As you can see, the dolphin kick is superior in speed, but it is also more demanding. For swimmers who struggle with the dolphin kick, a flutter kick can be a temporary alternative, but the dolphin kick is worth mastering.

Putting It All Together: A Sample Practice Set

To put these techniques into practice, try this set at your next workout. It is designed for intermediate swimmers and takes about 30 minutes.

• Warm-up: 400 easy swim (any stroke), 200 kick with board (choice)
• Drill set: 6 x 25 as follows: 25 dolphin kick on side, 25 vertical dolphin kick (10 seconds), 25 underwater kick with fins, 25 kick on back, 25 underwater kick with board, 25 breakout kick. Rest 20 seconds after each.
• Main set: 8 x 50 freestyle, each with 15 meters underwater dolphin kick off the wall. Try to maintain a consistent split time, and count your kicks on each length.
• Cool-down: 200 easy backstroke, 100 choice.

By focusing on body position, kick timing, breath control, and specific drills, you can transform your underwater dolphin kick from a weakness into a weapon. Start with the drills, be patient, and you will see your times drop.