Butterfly

Start with the whole stroke, then work on one part at a time. Most butterfly problems are timing problems, so give that section the most time.

The whole stroke

• Swimming Butterfly: The Complete Guide – U.S. Masters Swimming: body position, kick, pull and timing, each with drills, sets and dryland exercises. Start here.
• Butterfly technique – Russell Mark's slide deck for USA Swimming (archived copy, PDF)

Body position

• Butterfly Body Position Drills – USMS

Kick

• Butterfly Kicking Drills – USMS
• Butterfly kicking: a visual aid – USA Swimming: making the two kicks match
• Butterfly: both kicks should be created equal – USA Swimming (archived copy)

Pull

• Butterfly Pull Drills – USMS

Breathing and timing

• Butterfly Timing: Perfect Your Rhythm and Coordination and Butterfly Timing Drills – USMS: skate drill, one-arm butterfly, 3-2-1 breathing
• Don't Let Your Butterfly Beat Drop – USMS

Drills

• All the USMS butterfly drills, from basic to advanced: body position, kick, pull and timing.

More to watch

Swim fast butterfly with Michael Phelps:

Michael Phelps, underwater camera: