Q: I'm not comfortable with decline bench presses. Will this exercise help me?
A: Decline bench presses have a controversial reputation, but if they fail to produce gains in chest mass, it's usually because they are misunderstood and misused.
As an overall mass builder for your chest, decline bench presses cannot begin to compare with flat or incline bench presses. However, for hammering a foundation of muscle into place across the bottom of the pecs, so that it lifts your entire chest up and out and prevents it from sagging, decline bench presses are the answer.
For a complete physique, you need them all, and you need to know how not to do them, as well as how to do them.
WHEN NOT TO DO DECLINE BENCH PRESSES
Do not use them as a replacement for flat or incline benches. This causes the upper chest to remain flat and sunken, and the lower pecs to protrude like a lip, giving their chests a slanted appearance, as if they're sliding down their bodies.
Do not use them solely because they're easy. You may find decline bench presses uncomfortable at first, but I'm convinced that, once you become accustomed to them, you'll find the decline position most comfortable.
Use decline benches only to muscle up your bottom pecs. Depend upon flat and incline presses for the greatest bulk of your chest mass.
Do not start your chest workout with decline bench presses. Your first exercise should be the movement that requires your maximum output of strength to activate the most muscles of the bodypart in a compound manner (i.e., flat or incline bench presses, deltoids, triceps, lats).
After that, I proceed to exercises that hit specific areas, such as flyes for deep separation between my pecs and declines for the supporting strap of muscle at the bottom.
WHEN TO DO DECLINE BENCH PRESSES
Do them last. The invisible bugbear of bodybuilding is a thing called gravity, which is the tendency of everything, even our muscles, to be pulled downward.
With this in mind, you should prioritize your energy expenditures so you build overall mass with your first exercise, upper chest with your second exercise, lateral pecs with your third and lower pecs with your fourth.
Do them every second or third workout. Decline bench presses facilitate the use of heavier weight and build lower-pec mass quickly and easily, so do them only every second or third workout.
Keep an eye on how the symmetry of your chest is progressing. If it starts taking on a cantilevered look, cut back on your decline bench presses even further; to once a month, if necessary.