PrimarySecondaryNot worked
This movement mainly trains chest, and also recruits Front delts, Triceps.
The fly isolates horizontal adduction by taking the triceps out of the equation. It loads the chest where pressing loads it poorly: stretched, arms open, at the muscle's longest.
Twelve to twenty reps, moderate load, elbows slightly bent and locked there for the whole movement. A complement, never the backbone of a chest session.
Going deeper than the shoulder tolerates in search of more stretch. The joint takes the strain before the muscle does, and this is the movement where that costs the most.
The variants REPWIND's catalogue carries, under the name the app shows:
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