Butterfly: kicks with too much knee bend

Bends sharply at the knees so the feet thrash at the surface instead of a wave that starts at the chest and hips.

Activities that help

• Body Wave Glide – From a streamlined glide, swimmers make a gentle wave from chest to toes – the movement that drives dolphin kick and butterfly.
• Vertical Dolphin Kick – Dolphin kick upright in deep water, holding a noodle, so swimmers feel the kick start from the chest and hips rather than the knees.