Butterfly Stroke Technique: Timing, Rhythm, and Power
Good butterfly technique means two dolphin kicks per arm cycle — one as your hands enter, one as they exit — with the body moving in one continuous wave from chest to toes. Formfix checks all of this from a single iPhone video and returns a 0–100 score with the #1 thing to fix in under 15 seconds.
Butterfly is a rhythm stroke: when the timing is right it feels almost easy, and when it's off it's the hardest stroke in swimming. This page covers what good technique looks like, the mistakes that break the rhythm, and how to film your stroke for analysis.
Download Formfix on the App StoreWhat good swimming butterfly form looks like
Two kicks per cycle
A small kick as your hands enter the water and a bigger kick as they exit past your hips — the second kick drives your body forward into the recovery.
Body wave, not seesaw
The movement flows from chest to hips to feet in one wave — not the whole body bouncing up and down as one piece.
Simultaneous arm recovery
Both arms recover together, low over the water with relaxed, straight-ish arms — not high and muscled.
Keyhole pull
Underwater, the hands sweep out, then in under the chest, then push back past the hips — like tracing a keyhole.
Forward, low breath
The chin skims the surface to breathe — head forward, not up — and returns before the hands enter.
Hips at the surface
Your hips stay high throughout — when the hips drop, the stroke turns into an uphill climb.
Most common mistakes and how to fix them
One-kick butterfly
Why it happens: Skipping the second kick (at hand exit) removes the boost that lifts your body into the recovery.
Fix it: Cue 'kick in, kick out.' Do body-dolphin drills with arms at your sides, feeling both kicks, then add the arms back.
Breathing too high
Why it happens: Lifting the head straight up drops the hips and stalls the stroke.
Fix it: Cue 'chin on the water.' Breathe low and forward — your eyes should look at the water a few feet ahead, not at the wall.
Seesawing up and down
Why it happens: The whole body bouncing as one piece means the wave isn't traveling through the body.
Fix it: Cue 'chest presses, hips answer.' Practice vertical dolphin kick and body-wave drills — the chest initiates and the wave flows to the toes.
Arms recovering too high
Why it happens: A muscled, high recovery wastes energy and drops the hips.
Fix it: Cue 'swing low and relaxed.' The arms should skim the surface — if your shoulders burn after 25 meters, the recovery is too high.
Short, choppy underwater pull
Why it happens: Not finishing the pull past the hips shortens the most powerful part of the stroke.
Fix it: Cue 'push to your thighs.' Finish each pull with your hands brushing your thighs — the exit kick pairs with that push.
How to film it for analysis
Camera angle
Side-on at the waterline from poolside shows the body wave, timing, and breathing height. Underwater side-on (waterproof case) shows the keyhole pull and both kicks.
Distance
10–15 feet (3–4.5 m) along the lane from poolside; underwater, 3–6 feet (1–2 m) from the swimmer's line.
Framing
Keep the phone still and film 3–4 full stroke cycles. The stroke is rhythmic — one cycle tells you little, four show whether the timing holds.
FAQ
What is the correct butterfly stroke technique?
Two dolphin kicks per arm cycle — one at hand entry, one at exit — with a body wave from chest to toes, a low forward breath, and arms recovering together low over the water. The rhythm matters more than the strength.
Why is butterfly so tiring?
Usually a timing problem, not a fitness one. Without the second kick at hand exit, you're dragging your body through the recovery. When both kicks are timed right, the stroke carries itself forward.
How many kicks per stroke in butterfly?
Two: a smaller kick as your hands enter the water and a bigger one as they exit past your hips. The exit kick is the one most swimmers miss.
How do I breathe in butterfly?
Low and forward — chin skimming the water, eyes looking a few feet ahead — timed as your arms pull through. Your head should return to neutral before your hands enter. Lifting the head up drops your hips.
How do I film my butterfly for a form check?
Side-on at the waterline from poolside, or underwater with a waterproof case, filming 3–4 stroke cycles. Upload to Formfix for a 0–100 score and the #1 fix in under 15 seconds.
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