The primary muscle targeted by decline dumbbell flyes is your sternal pectoralis major, along with the anterior deltoids and your biceps. To a lesser extent, you use the triceps and wrist flexors in decline dumbbell flyes as well. Some trainers think this exercise represents a good transition between a bench press and a cable cross because it enhances the depth and size of chest muscles.
Lie down on a decline bench with a dumbbell in each hand, and raise the dumbbells above you. While keeping your back and legs straight, lower the dumbbells. Slightly bend your elbows as you bring the dumbbells to a position parallel with the ground. Now, contract your pectoral muscles and bring the dumbbells back into the position with which you began. The motion you use when elevating the dumbbells resembles a hugging motion. Repeat this exercise 10 to 12 times.
For the decline dumbbell to effectively work your pectoral muscles, make sure both the up and down movements are initiated and perpetuated by contracting your chest muscles and not the deltoids. Because the two-handed, parallel grasp of the dumbbells fundamentally places emphasis on the deltoids, concentrate on using your pectorals to keep the exercise effective. In addition, you should pay strict attention to form to reduce your risk of injury.
To avoid injury, keep your back and head in contact with the bench throughout the exercise, and concentrate on hyperextending your wrists so that you bring the wrists together rather than the dumbbells. Remember not to suddenly snap out of the movement when your arms are extended above you. When lowering the dumbbells, use reactive elbow flexion to reduce your potential for elbow strain. Finally, your biceps and forearms should make a right angle as they pass by the chest in the lowering phase.
Performing variations of the dumbbell fly will work your chest, shoulder and arm muscle subgroups while also continuing to enhance the main muscles. You can perform dumbbell flyes on decline or incline benches, as well as exercise balls. When you're lying on an incline, your upper pectorals and anterior deltoids receive the most resistance, while a decline bench allows you to lift greater weights while employing the same basic muscles that you use on a regular bench press.