Butterfly Biomechanics

Base positions

• Chin tucked, eyes looking to the bottom
• Head on or close to the surface of the water
• Shoulders square
• The body should undulate, in time with the kick
• Arms straight, on surface, shoulder width apart

Kicking Action

• Feet together
• The kick should start at the head and move in an undulating fashion to the feet
• The knees should bend and drive the water up and down
• The kick should accelerate in both the up and down beats
• Propulsion is gained from both the up & down kicking action

Arm action (Recovery)

• Arms over the water (with speed), thumbs pointing down
• Elbows straight (small bend in early recovery acceptable)
• Hands relaxed on entry
• Soft arm entry, approximately in line with shoulders
• Hands drive (reach) forward, not downwards

Timing

• First down kick on hand entry (small), bum rises & breaks the surface
• Chin down, hands in, bum up
• Second down kick on push under the hips
• Chin up, kick & push back
• The push and second kick help propel the arms over the water and greatly assist breathing

Arm action (Propulsion)

• Arms fully extend after entry
• Small out sweep (hand pitch: palms out)
• In-sweep to mid line of body (hand pitch: palms back)
• Hands almost touch under body
• Strong push to upper thigh (hand pitch: Palms turn slightly in)
• Hands accelerate through the propulsive phase

Breathing

• Chin rises during middle pull (in-sweep)
• Chin rises before second down kick
• Chin forward on surface for breathing
• Chin tilts down, fore head hits water surface
• Chin down prior to hand entry

Time line of teaching

• Teach streamlining
• Teach kick with hip undulation
• Basic arm action (arms round and over)
• Timing (very important)
• Breathing (natural), ensure correct timing
• Advanced arm action