Butterfly No Longer a Nightmare: A Scientific Breakdown of Dolphin Kick, Two-Beat Kick, and Energy-Saving Rhythm

Butterfly Is Tiring Because You’re Fighting It

Butterfly is considered the hardest and most exhausting stroke, yet elite swimmers make it look as effortless as dolphins. The difference lies in this: butterfly’s power comes from wave transmission, not from pulling hard with your arms. When you try to “pull yourself out of the water with your arms,” you burn through your energy; when you learn to let the wave travel from your chest to your toes, butterfly becomes surprisingly rhythmic.

The Dolphin Wave: A Wave That Starts from the Chest

The core of butterfly is the dolphin undulation, and the wave travels in this sequence: chest → hips → knees → ankles. The initiation point is pressing the chest down, not the legs. When the chest presses down, the hips naturally rise, the wave transmits downward, and finally the propulsion is whipped out through the soles of the feet.

Key sensation: imagine your body is a whip from head to toe, with the chest as the handle and the soles of the feet as the tip.

The Timing of the Two Kicks (This Is the Key to Saving Energy)

One butterfly arm cycle includes two kicks, and their timing is completely different:

Get the timing of the second kick right, and the arms will exit the water with almost no effort—this is the dividing line between “struggle butterfly” and “efficient butterfly.”

Breathing: The Lower, the Better

Most butterfly breathing failures come from lifting the head too high, which causes the hips to sink and the next cycle to collapse. The correct approach: use the body lift generated by the second kick, keep the chin skimming the water surface as you move forward, expose only the mouth to inhale, keep your gaze forward and downward, and tuck the head back down immediately after inhaling.

Four-Week Butterfly Development Plan

• Week 1 | Wave Awareness: 6×25 m “dolphin kicks” (arms extended forward or pressed against the body), feeling the wave initiated by the chest.
• Week 2 | Single-Arm Butterfly: 6×25 m single-arm butterfly (other arm extended forward), alternating left and right, focusing on the two kicks.
• Week 3 | Rhythm Butterfly: 8×25 m, swimming only 6–8 full strokes per lap, prioritizing complete technique over speed.
• Week 4 | Integration: 6×50 m (25 butterfly + 25 freestyle recovery), gradually extending continuous butterfly distance.

For distance swimmers and triathletes, even if you don’t race butterfly, training it is still extremely valuable: it significantly strengthens core linkage and body wave, making your freestyle smoother and more efficient.

Coach’s note: Don’t ask “how many meters can I swim butterfly,” ask “how many meters can I maintain perfect technique.” Better to swim 6 perfect butterfly strokes than 20 collapsing ones. Quality always comes before quantity.

Treat butterfly as part of your core training, and you’ll get more back than just one stroke.

Related Reading

• The Dolphin Wave in Butterfly: A Beginner’s Breakdown of Spinal Rhythm and Core Transmission
• Coordination Training for Butterfly Dolphin Kick and Body Wave
• Butterfly Wave Mechanics: Coordination Training for Hip Drive and Arm Synchronization
• Butterfly Entry and Exit Rhythm: Balancing Streamlining and Propulsion