Dumbbell flyes are an exercise that can help to strengthen the chest and shoulders. They are performed by lying on your back on a flat or incline bench and holding dumbbells in your hands, then extending your arms to point up toward the ceiling and bending your arms slightly, with your palms facing each other. You then arc your arms down, squeezing your shoulder blades together, and lower your fists until they are just above the height of your chest.

Dumbbell flyes work the following muscles:

• Chest: Both your pectoralis minor and major work hard when you are doing a dumbbell fly. Your pectorals start in the middle of your chest and run out toward your shoulder and upper arm. You use them when you move your shoulder to push something or when reaching back to scratch your back.
• Shoulders: A dumbbell fly works the front and middle parts of your deltoid muscles in your shoulders, with some secondary strengthening of your posterior deltoids in the back of your shoulders. Your deltoids start at your shoulder blade and collarbone stretch over your shoulder, attaching to your upper-arm bone. With these muscles, you extend, flex, and rotate your arm.
• Triceps: The triceps muscles in the back of your upper arms are also used to help stabilize the weight during the exercise.

While the main focus of a dumbbell fly is on your chest, it will also target muscles in your shoulders, back, and arms which are used to help stabilize the weight during the exercise. However, some fitness experts argue that there are better and safer alternatives to dumbbell flyes, such as push-ups, cable crossovers, and chest dips.