Your pecs, short for pectoralis major, are your main chest muscles. Although all chest exercises affect the whole of the chest, it is possible to place an emphasis on the upper, middle or lower fibers by performing specific exercises. Developing muscle mass, a process called hypertrophy, requires that you lift heavy weights and perform multiple sets of six to 12 repetitions. It is also important to consume a surplus of calories and adequate protein to fuel muscle growth.
Decline Bench Press
The regular bench press is one of the most popular and effective pec exercises. Performing this exercise on a decline bench shifts the emphasis onto your lower pecs. Set an exercise bench to a 20 to 30 degree decline. Lie on the bench so that your head is lower than your hips. Grasp a barbell with an overhand and slightly wider than shoulder-width grip. Hold the weight over your chest. Bend your arms and lower the bar to the bottom of your chest. Pause in this stretched position for one to two seconds and then drive the bar back up to arms' length. This exercise can also be performed using dumbbells.
Parallel Bar Dips
Parallel bar dips use body weight to develop your lower pecs. This exercise is also effective for building strength and size in your triceps and anterior deltoids. Grasp the bars and then support your weight on extended arms. Bend your legs and cross your feet behind you. Lift your chest, arch your lower back slightly and then bend your arms. Lower your chest between your hands as far as feels comfortable. Push back up and then repeat. If you can complete 12 or more repetitions, make this exercise more demanding by tying a weight around your waist or wearing a weighted vest.
Unlike all pressing exercises, dumbbell pullovers involve movement only at your shoulder joint. This means that there is minimal involvement of the triceps in this exercise. Lie length-ways on an exercise bench so that the back of your head is resting on the very edge. Hold a dumbbell in two hands and press it to arms' length over your chest. Bend your elbows slightly. Keeping your butt firmly pressed into the bench, lower the dumbbell over your head until your arms are next to your ears. Hold this stretched position for a second and then pull the dumbbell up and over to return to the starting position. Avoid excessively arching your lower back or lowering the dumbbell too far behind your head because this can lead to injury.
High to Low Cable Crossovers
The angle at which your perform cable crossovers affects the part of your pecs that this exercise emphasizes. The high to low angle focuses on your lower pecs. Set the pulleys around head height and, with your back to the machine, hold a handle in each hand. Step forward and reach out so your hands are at shoulder-height and your arms resemble a T shape. With a slight bend in your elbows, draw your arms inward and downward so they meet in front of your hips. Slowly return to the starting position and repeat.