[Dumbbell Back Fly] can exercise the rear and side muscles of the deltoid muscles. Stand upright with your feet shoulder-width apart. Lean your upper body forward and keep your back straight. Hold a dumbbell in each hand directly under your chest. Turn your wrist slightly to ensure that your little finger is higher than your thumb. Slowly raise your arms to both sides, choose an appropriate weight, and make sure you can do a maximum of 15 times each time.
