Why the Underwater Dolphin Kick is So Exhausting to Grasp

Fast underwaters are one of many necessities for swimmers trying to kick butt on race day.

But the fifth stroke can be the toughest to grasp.

Compared to the opposite strokes, dolphin kicking forces swimmers to attempt to resolve a number of issues on the identical time:

• You’re not respiratory.
• You’re producing propulsion with a few of the largest muscular tissues within the physique.
• And it’s a must to coordinate and time a fancy motion from the trunk to your toes.

Longer, extra dolphiny breakouts include some prices.

Better understanding them will will let you train the dolphin kick like a pro and deploy it extra neatly on race day.

Breathing constraints

Let’s begin with the obvious trade-off that we’re making after we dip, dive, and push-off below the floor to dolphin kick—holding our breath!

Every further kick we take means additional delaying sucking down our subsequent breath. Oxygen availability goes down, CO₂ creeps up, and that not-fun discomfort/panic rises in our throats.

As oxygen availability is proscribed, swimmers are pressured to show to their anaerobic system to maintain producing power.

A examine by (Venckunas & Achramavicius, 2024) checked out what occurs when swimmers prolonged their underwaters past their ordinary breakout distance throughout a below-threshold 200m freestyle.

Instead of their ordinary 4-5m breakouts, swimmers have been instructed to kick out to 12.5m off each wall. Blood lactate shot up with the longer kick-outs:

• Regular underwaters: 3.3 mmol/L.
• Long underwaters: 7.9 mmol/L.

Extending their underwaters pushed swimmers deeper into anaerobic territory.

Fewer breaths, extra reliance on anaerobic power to maintain them swimming quick.

Metabolic constraints

Dolphin kicking can be straight-up metabolically costly, even after we aren’t pushing past our ordinary kick-out distance.

Unlike full-stroke swimming, the place power is unfold between the legs and arms, underwater kicking depends closely on a few of the largest muscle teams within the physique to generate propulsion.

And they work laborious.

• The trunk initiates the motion, creating important oscillation and bracing the backbone
• The hips drive laborious in each instructions, creating a robust physique wave
• The quadriceps, hamstrings, calves, and even your shins all hearth intensely to show it into propulsion

And all of these things occurs because the decrease physique is snapping backwards and forwards aggressively.

Compared to the freestyle kick, dolphin kicking makes use of manner bigger amplitude and elevated power price. And it’s much more costly than full-stroke swimming.

A examine printed earlier this yr (Segovia-SanBenito et al., 2026) in contrast what occurred when swimmers did 25s quick of:

• Underwater dolphin kick
• Full-stroke swimming
• Using a standard kickout (common of seven.1m) after which swimming the remainder of the size

Things like oxygen saturation, perceived effort, and coronary heart fee have been comparatively the identical throughout the board. But lactate was the place issues received a little bit wild.

Dolphin kicking produced lactate values that have been virtually 50% larger than floor swimming… though perceived exertion and oxygen saturation have been virtually the identical.

Swimmers have been paying a giant power invoice however not essentially feeling the metabolic price.

This is essential to recollect as a result of swimmers are dolphin kicking repeatedly, flip after flip, when racing. Swimmers want to coach this ability laborious and put together to maintain the metabolic calls for of the ability on race day.

Technical constraints

And then comes the trickiest half… mastering the motion of the kick itself.

Dolphin kicking is a very complicated motion whenever you start to interrupt down the entire stuff that goes into it.

Swimmers want to have the ability to:

Technique errors can shortly compound into decreased effectivity (and bear in mind—it’s  already metabolically thirsty!) and speeds.

Dolphin kicking appears to be like straightforward and clean when it’s finished at a excessive degree as a result of these swimmers have mastered method and timing.

They’ve put within the reps. Hit their kick counts. Worked on the ability persistently. And refined the main points.

Why It’s Worth the Work

Despite the challenges that come together with the underwater dolphin kick, there’s a pay-off for the swimmer who rises to the issue of the duty.

Underwaters could make as much as 60% of your race in a brief course pool. (A smidge longer in brief course yards.)

And swimmers can journey sooner underwater than on the floor.

Leading to sooner outcomes on race day.

So, be the swimmer who can handle the respiratory calls for, tolerate the metabolic price, and grasp method.

Happy kicking!

---

ABOUT THE AUTHOR

Olivier Poirier-Leroy is a former national-level swimmer, 2x Olympic Trials qualifier, and writer of a number of books for swimmers, together with The Dolphin Kick Manual: The Swimmer’s Ultimate Guide to a Fast Underwater Dolphin Kick.

The e-book is a beastly 240+ pages of actionable insights and analysis into elite dolphin kicking method and efficiency. It particulars every part from mastering undulation to vortex recapturing to structuring a dryland program for dolphin kicking success.

The Dolphin Kick Manual combines evidence-based insights with a group of 20 ready-to-go units and a 6-week Action Plan to assist swimmers set a course for dolphin kicking success.

Train smarter and kick sooner.

👉👉👉 Learn more about The Dolphin Kick Manual