Although the top portion of the muscle aids in the action of the pec deck fly, its primary focus is on the sternal, or lower, region of the muscle. Pectoral Minor Muscle: Subordinate to the pec major, this muscle is less bulky and more flattened. For quite some time, the bench press has been the go-to exercise for developing ones chest and arms. However, a user may be surprised to learn that there are other options that are just as enticing when it comes to making the pecs pop! Pec deck machine-based chest workouts are one example. Full chest activation is hindered by the bench press and other pec workouts since they rely on such a small range of motion.