Dumbbell Bent-Over Flys target the rear delts (back shoulder muscles), traps (trapezius, upper back), and rhomboids (mid-back muscles between the shoulder blades). Hold a dumbbell in each hand, hinge at the hips, and keep your back straight. With a slight bend in the elbows, lift the dumbbells out to the sides until shoulder height, then slowly lower them back. This exercise enhances upper-back definition, strengthens the shoulders, and improves posture while maintaining proper form.