Shoulders shrug during the fly
Upper traps initiate instead of posterior delts and rhomboids.
Overactive muscles
Upper trapeziusLevator scapulae
Corrective work
Foam RollUpper traps↗StretchLevator scapulae stretch↗Upper traps initiate instead of posterior delts and rhomboids.
Elbow flexion reduces the rear delt lever arm.