Butterfly: the importance of the leg kick

Training & Technique
Written by: arena coaches at 16 February '16 0
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The butterfly is the most complicated stroke to swim properly, because it requires more stamina, greater flexible strength and better coordination.

The first two are more closely interrelated for swimming the stroke properly, so let’s see why.

One of the most common mistakes when swimming this style, and something that certainly makes it harder to swim for a long time without stopping, is the lack of a leg kick during the arm stroke.

As we have seen, there are two leg kicks but most people learning this stroke only make one. This makes swimming the butterfly more tiring and less efficient.

The first leg kick, performed just as your hands enter the water, is the shorter and less powerful of the two.

At this point your speed is at its lowest, because your hands slow down your body’s forward motion as they enter the water; here the leg kick cancels out the braking effect of your arms and raises your hips, so that you can pull properly with your hands (fig.1)


fig 1

The second leg kick, performed as you complete the pull phase, is longer and more powerful than the first and helps push up your hips that have been “pushed down” by the movement of your arms (fig. 2).


fig. 2

This extremely long and energetic gesture, combined with the final part of your arm pull, results in your highest forward speed.

What happens if you only use a single leg kick?

When you do not have the strength to really push back with your arms, your hands come out of the water halfway through the stroke and there is no time to insert a second leg kick.

So, to try and avoid or correct this flaw, you will have to focus on your arm pull (as well as practising your leg kick) making sure it continues until both arms are completely extended and only then should you begin the recovery phase.

If you find this movement overtiring, reduce the length of the various parts of your stroke, relax one arm at a time and lengthen your recoveries.

arena How to swim butterfly

As you regularly devote time to learning how to swim the butterfly, here is a rather simple technical drill that will allow you to train properly without getting overtired and concentrate to the maximum on the length of your arm pull and strength of your leg kick.


DRILL: 2 x (16 x 25 + 200 legs)

RECOVERY: 20” between 25 m reps– 1’ between legs


  1. butterfly using only right arm, other arm by side
  2. slow freestyle
  3. butterfly using only left arm, other by side
  4. slow backstroke
  5. slow butterfly with longest possible stroke
  6. double-slow backstroke
  7. butterfly at max speed for 12.5 m + 12.5 m slow freestyle
  8. double-slow backstroke

Once you have learned how to coordinate your arms and legs properly and are strong enough to really pull through with your hands, swimming the butterfly will be all downhill.


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arena coaches

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