Flutter Kick: Swimming technique, drills and fixes

The flutter kick is the alternating up-and-down leg kick of freestyle and backstroke. Your arms do most of the work, but the kick still adds real propulsion, more so when you sprint, and it helps keep your hips up so you drag less. A good kick starts at the hip and whips down through a softly bent knee to a loose, pointed foot, small and fast, right at the surface.

Kick from the hips

Start each kick at the hip, then let the knee and ankle follow in order, like cracking a whip. The speed builds toward your foot.

a wave that starts in your middle and runs out to your toes.

On the downbeat, let the knee bend softly, about as much as it bends in a walking stride. Don't start the kick by bending the knee. That kills the whip and drops your knee deep into the water.

the leg swinging from the hip, the knee just giving a little.

On the upbeat, bring the leg up nearly straight. Your heel can just break the surface at the top.

long, almost straight legs on the way up.

Relax the ankles

Point your toes and keep your ankles relaxed so the top of your foot faces back toward the wall behind you. The top of the foot is what pushes water backward on the downbeat.

loose, floppy feet that flick at the end of each kick.

Small and fast

Keep the kick small: the downbeat goes only about a foot (around 30 cm) deep, and your feet stay inside the width of your body. A bigger kick mostly adds drag.

your legs hiding in the shadow of your body.

Kick right at the surface, fast rather than big. A foot thrashing in the air can't push water, so aim for a small boil, not a big splash.

quick, light kicks with only a little white water.

Match the kick to your stroke. In freestyle the base rhythm is two main kicks per arm cycle, one with each arm. A six-beat kick adds two smaller kicks per leg between those. Start relaxed and steady before you try to kick hard.

the kick falling into rhythm with your arms, not fighting them.

Feel it

Long legs, a soft knee and floppy ankles, with the motion coming from your hips. The kick feels quick and light, right under the surface, with your heels just breaking the top. In backstroke, your knees stay under the surface. If you hear loud splashing or feel your thighs working like you're pedaling a bike, make the kick smaller and start it from the hip again.

Fix-its

You kick from the knees (bicycle kick) Straighten the legs and start the kick at the hip. Vertical kicking and kicking on your back with your knees under the surface both train this.
Your legs are locked and stiff Don't overcorrect. Let the knee bend softly on the downbeat and keep your ankles loose so the foot can flick.
Your feet kick out of the water and splash Keep the kick right at the surface. Only the heel should break the top on the upbeat.
Your kick is too big or too wide Shrink it to about a foot deep and keep your feet inside your body's width. Kick faster, not bigger.
Your ankles are stiff and your feet point down Relax and point your toes so the top of the foot faces back. Add the ankle stretches in the drill list.

Drill

Back kick in streamline: 2 x 25, small fast kicks from the hip, knees staying at or under the surface.
Wall kick: hold the wall and kick 4 x (25 seconds on, 35 seconds rest), keeping the kick small and at the surface.
Vertical kick in deep water: 4 x (20 seconds on, 20 seconds rest), legs nearly straight and kicking from the hips. Only do this in water you're comfortable in, near the wall.
Side kick and snorkel kick: 2 x 25 of each, keeping the kick tight and inside your body's width. A head-up kickboard kick doesn't put you in your swimming position, so use these instead.
Ankle range on dry land: ankle sits (kneel back on your heels, tops of the feet flat) and ankle alphabets (trace A to Z with your toes). Build the time slowly and stop if it hurts.

Sources

Last checked 2026-10-25.