The “boxer’s cut” muscle definition -- sleek, well-defined chest muscles -- comes through development of your side-chest muscles, the serratus anterior muscles located at the sides of your ribs. Side-chest muscles allow protraction of the scapula, or movement of your shoulders over your rib area. Movements that extend your arms out in front of your chest work these particular muscles. You can perform an assortment of exercises to target these muscles with various pieces of exercise equipment.
This exercise requires no extra equipment to work the serratus muscles. Assume a standard plank position with your forearms on the ground and your elbows in direct alignment with your shoulders. Extend your body in a straight line. Keep your feet flat on the floor and your elbows bent at a 90-degree angle. To perform the plank plus, collapse your elbow joints by bending your elbows until your forearms and upper arms touch. Now, engaging your side-chest muscles, push down on your forearms until the your elbows return to the 90-degree angle.
Lie flat on your back on a bench with your feet flat on the ground. With an overhand grip, grasp the barbell so that your hands are spaced shoulder-width apart. Unrack the bar and center it over the middle of your chest with your arms fully extended. Now, extend at your shoulders, forcing the bar upward as you lift your shoulders as high up off the bench as possible. Once this position is reached, lower your shoulder blades back to the bench. As soon as your shoulders touch the bench, repeat the exercise.
Resistance Band Boxing
This exercise requires one medium-length resistance band. Grip one end of the resistance band in each hand and wrap the band around the middle of your back, just below your shoulders. Keeping your elbows tight to your side and your hands close to your shoulders, punch forward with your right hand, making sure your left hand doesn’t move. Now, quickly bring your right hand back, and punch forward with your left hand, making sure the right hand doesn’t move. Alternate back and forth to target the serratus muscles.
If you want to develop your side-chest muscles for a particular sport, choose exercises that develop absolute strength or strength endurance, according to the needs of the sport. For absolute strength, the best choice is the barbell protraction exercise, while the resistance-band boxing exercise develops strength endurance. For boxers, barbell work can help you achieve knockout power, but if you want your strength to last for the duration of the fight, include resistance-band exercises in your workout routine.