Pec Deck (Butterfly Machine)

Technique

Sit in the machine with your back against the pad and forearms resting on the pads, elbows slightly bent. Bring your arms together in an arcing motion, squeezing the chest at the end range. Slowly return to the start, feeling a stretch across the chest. Avoid using momentum or jerking the weight.

Steps

1. Adjust the seat so your elbows align roughly with your shoulders
2. Press your back firmly against the pad
3. Place your forearms on the pads with your elbows slightly bent
4. Bring the pads together in a controlled arc
5. Squeeze your chest briefly at the end range
6. Return slowly until you feel a comfortable chest stretch

Common mistakes

• Rounding the shoulders forward as the pads come together
• Letting the elbows drop well below shoulder level
• Allowing the weight stack to pull the arms too far back
• Jerking the pads together with momentum

Variations

• Neutral-grip pec deck with vertical handles
• Single-arm pec deck fly
• Alternating-arm pec deck fly
• Seat-height-adjusted pec deck fly

FAQ