The serratus anterior muscle runs from the lateral surface of your ribs to the inside border of your scapula. This muscle plays an important role in horizontal arm movements such as pushing and punching and is often called the "boxer's muscle." Keeping this muscle strong defines your chest and keeps your shoulder joint stable and healthy.

Incline Press

Perform this exercise with dumbbells or a barbell to work the serratus anterior as well as the pectoralis major, anterior deltoids and triceps brachii. Sit on an incline bench angled at 45 to 60 degrees. Press your back firmly into the backrest and grasp the bar with an overhand grip wider than shoulder width. Lower the bar to your chest, then press it vertically by extending your arms.

Dumbbell Incline Shoulder Raise

This exercise isolates the serratus anterior muscles. Sit on an incline bench angled at 45 to 60 degrees. Hold a dumbbell in each hand and position the weights above your shoulders with your arms extended. Keeping your arms straight, raise your shoulders toward the dumbbells as high as possible. Pause, then lower your shoulders back to the bench.

Dumbbell Pullovers

Dumbbell pullovers work to strengthen the serratus anterior, pecs, triceps, latissimus dorsi and rhomboids while also stretching and expanding the rib cage. During the exercise, the serratus anterior, rhomboids and pectoralis minor stabilze the scapula so that the humerus can move from a stable base. Lie on a horizontal exercise bench with your knees bent and feet flat on the floor. Hold a dumbbell in the palms of both hands with your thumbs surrounding the handle. Begin with your arms extended vertically above your chest. Slowly lower the dumbbell behind your head, bending slightly at the elbows. Contract your back and chest to pull the dumbbell back to the starting position.

Medicine Ball Power Drops

This is a dynamic exercise that works not only your serratus anterior but also the muscles of your shoulders, arms, chest and abdomen. You will need a training partner to complete this exercise. Lie on the floor perpendicular to an exercise bench with your head near the bench. Bend your knees, place your feet flat on the floor and extend your arms vertically above your chest. Have your partner stand on the bench and hold a medicine ball, then drop the ball straight down to your outstretched hands. Catch the ball with both hands and allow it to fall all the way to your chest while controlling its deceleration. Once the ball reaches your chest, explosively push it away from your chest and into the air so that your partner can catch it.