What uneven arms are
Uneven arms in butterfly means one arm enters or recovers before the other, so the two sides of the stroke are out of step.
It often grows as you tire, and it can be easy to miss from inside the water.
Why they cost you
Butterfly needs both arms working together. A lag between them twists the body and breaks the wave that the stroke rides on.
The kick then has to make up for a pull that is no longer working as one.
How to fix them
Enter and recover both hands at the same moment, about shoulder width apart.
Keep the head central when you breathe, with the chin sliding forward along the water rather than turning to one side.
Swim short efforts with rest between them, so you practise the even stroke rather than the tired one.
One drill to try
- Swim slow butterfly over a short distance.
- Check that both hands land in the water together, at the same width.
- End the effort as soon as the timing slips, then rest and go again.
How to film it so Llyr can read it
Film this one head-on. Stand your phone on the deck at the end of your lane, facing you, and swim toward it.
From the side, the far arm hides directly behind the near one, so the two cannot be told apart. Llyr shows you how to frame the shot.
Already have a clip? You can import a video you filmed earlier. Read the full filming guide.
What you see in Llyr
When the arms fall out of step stroke after stroke, Llyr names it Arms uneven and shows it on a still from your own video.
Its glyph is a tick from the dashed centre line out to the point that sits off it.
The cue to take into your next set is Enter both sides together.
Llyr is a second set of eyes, not a coach. Check each correction on the replay, and if your coach sees it differently, go with your coach.