How to Improve the Underwater Dolphin Kick (More Hips, Less Knees)
🐬 What you'll take away:
- 🦵 Why “kick harder and faster” is the wrong fix for a slow dolphin kick.
- 📊 The study that pinpointed exactly what faster underwater kickers do differently.
- 🌊 The difference between a smooth, powerful wave and a clunky, stop-start kick.
- 🛠️ 4 drills to build hip-driven power — in the pool and on dryland.
- ⏱️ Why you can't muscle your way to a great underwater (and what to do instead).
The underwater dolphin kick is some of the cheapest speed in swimming — off every start and every wall. So when a swimmer wants more of it, the instinct is to kick harder and faster. Here's the thing: that's usually the wrong fix. The real answer is one word — hips.
Most swimmers drive the kick from the knees, which produces a clunky, stop-start motion that bleeds speed. The fastest underwater kickers do the opposite, and the research is clear about it. Let me show you the fix and the drills that build it. 👇
🐬 How do you improve the underwater dolphin kick?
Lead with the hips. A study (Tsunokawa et al., 2025) found that faster dolphin kickers initiate each kick from the hips — the hips drive the movement, and the knees simply follow. The hips stay in charge throughout.
That sequencing creates a smooth, continuous wave that carries down the body and off the toes. The knee-driven version? A choppy, stop-start kick that looks busy but kills underwater speed.
One of the frustrating realities of an elite underwater dolphin kick is that you can't muscle through it. The timing has to be in place — and that starts at the hips.
🛠️ 4 drills to build a hip-driven dolphin kick
- Vertical dolphin kick — kicking upright removes the breathing limit so the swimmer can focus on the sequence: hips, then knees, then ankles.
- Side (fish) kicking — dolphin kicking on the side naturally grooves better hip-knee timing and undulation.
- Hip “flick” at each change of direction — a quick flick of the hips on the switch from up-kick to down-kick and back keeps the hips leading.
- Dryland for hip power — kettlebell swings, back extensions, and hip thrusts build both the strength and the awareness for hip-initiated movement.
Underwaters are a skill, which means they're trainable — and a few weeks of focused, hip-led work can transform them. This is exactly the kind of technical detail we obsess over at the Swimpros Performance Accelerator, Europe's most popular performance swim camp right now, where small mechanical fixes turn into real time drops.
🔑 Key takeaways
- Lead the dolphin kick with the hips, not the knees.
- Hip-driven kicking creates a smooth wave; knee-driven kicking is choppy and slow.
- Vertical kick, fish kick, hip flicks, and hip-focused dryland build the timing.
- You can't muscle an elite underwater — the sequencing has to be right.
❓ Swim parent FAQ
How do you improve the underwater dolphin kick?
Lead the kick with the hips, not the knees. Faster kickers initiate from the hips and let the knees follow, creating a smooth wave. Vertical kick, fish kick, and hip-driven dryland build that timing.
Hips or knees?
Hips. The hips drive and the knees follow. A knee-driven kick is clunky and stop-start, which kills underwater speed.
What drills help?
Vertical dolphin kick, side/fish kicking, a hip flick at each direction change, and dryland like kettlebell swings, back extensions, and hip thrusts.
Why does my swimmer's kick lack speed?
Usually it's knee-driven and the timing is off. Fix the sequencing — starting at the hips — and the speed follows.
📚 More for swim parents
Turn small fixes into real time drops
Underwaters, turns, and the details most clubs skip — drilled hard, with the mindset to match. That's the Swimpros camp. See it, or start free.
Explore the Swimpros camp →Or join the free Swimpros Skool group — no cost, no commitment.
Stop trying to kick harder. Start kicking from the hips. That single shift is what separates a busy dolphin kick from a fast one. 🟡
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