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Swimming

Butterfly Monofin Kick

The butterfly monofin kick uses a single fin joining both feet to practice a coordinated dolphin kick. It trains trunk control and leg endurance through a smooth wave from your torso to your feet.

Higher injury risk. Read the safety notes before adding weight.

  • Intermediate
  • Higher injury risk
  • Rest 45 sec

How to do it

  1. Fit both feet securely into the monofin while seated at the pool edge.
  2. Lower yourself into the water while holding the wall.
  3. Push off gently on your back with your arms at your sides.
  4. Start a small body wave by pressing your upper back slightly into the water.
  5. Let the wave travel through your hips toward your feet, allowing a slight knee bend.
  6. Sweep the fin up and down in a continuous rhythm for your chosen distance.
  7. Finish by taking hold of the wall.

Form cues

  • Keep your face above water.
  • Let your ankles stay supple.
  • Keep the splash small.
  • Breathe steadily throughout.

Common mistakes

  • Pedaling from the kneesKeep your thighs close to your body's line instead of pulling your knees toward your chest.
  • Exaggerating the back archReduce the wave's size so your lower back does not repeatedly bend to its limit.
  • Forcing every kickUse a relaxed rhythm that lets the fin flex rather than trying to overpower its resistance.

Safety

With both feet joined, you cannot use normal independent-leg kicking to recover if you become tired or panicked, creating a drowning risk. Forceful kicks against the fin's resistance can also strain your ankles or lower back.

  • Use a lifeguarded pool with a clear lane; never practice alone.
  • Practice floating and removing the fin at the wall before swimming away from support.
  • Do not walk or jump while wearing the monofin.
  • Stop at support immediately if you develop cramps, pain, breathing difficulty, or loss of control.

Choose an unassisted surface dolphin-kick drill first if you are not a confident swimmer, and seek professional advice before using a monofin with existing ankle or back pain.

Muscles worked

Front
Back

Primary muscles

  • Core

Secondary muscles

  • Calves
  • Glutes
  • Hamstrings
  • Hip Flexors
  • Quadriceps

Equipment

  • Pool Lane Line (optional)
  • Swim Monofin

Sets and reps

Sets
4–6
Target
10–25 meters
Rest
45 sec

This starting version stays on your back at the surface; focus on control rather than speed or underwater distance.

Variations

Easier