Chest exercises are generally designed to target the pectoralis major, a large muscle responsible for the flexion and adduction of the arm. The pectoralis major works in conjunction with a smaller, deeper muscle, the pectoralis minor. Collectively, these paired muscles are often referred to simply as 'the pectorals.' Although each pectoralis major is a single unit, chest workouts often target specific areas of the chest as if they were separate entities.
Many chest exercises, such as the classic bench press, work the chest area in a general way. These movements represent an excellent starting point for those who are new to resistance training. Other exercises are used to target the inner, outer, and upper pectorals separately. Once training advances beyond the novice level, a well-balanced workout usually includes chest exercises that target each area of the chest individually.
The upper pectorals are usually worked by any chest exercises performed on an incline bench. Generally speaking, a steeper incline targets a higher section of the chest. For that reason, it is typically recommended that the bench be set between 35 and 50°, depending on personal preference and comfort. Incline bench presses, incline dumbbell presses, and incline flyes are all good choices to target the upper pectorals.
Inner pectoral development adds noticeable definition to the sternum area on both men and women. Once considered one of the hardest areas to target, the inner pectorals are best activated by movements that allow the arms to come together, or cross in front of the body, at the end of each repetition. Cable crossovers and pec deck machines are designed to make this motion possible. If these machines are not available, dumbbell flyes can be substituted to mimic the same motion.
Perhaps the most neglected area of the pectoral muscles, the outer chest, is nevertheless an important target point. A well-developed outer chest gives the appearance of a narrowed waist and acts to balance the hips. This particular region is well-targeted by chest exercises requiring a wide grip, such as the wide grip bench press, and wide grip dips on the parallel bars.
As balance is important in all weight-training programs, it is recommended that chest exercises be complemented by exercises that stimulate those muscles that work in cooperation with the pectorals. Synergists of the pectorals — those muscles that assist in the exercises above — include the biceps, triceps, deltoids, and rotator cuff muscles. Antagonists, those that carry out movements opposite to those of the chest, include the rhomboids and latissimus dorsi. These exercises can take place either during the same workout, or on an alternate day.