Having a well-developed, “squared off” looking pectoralis minor is all but necessary to develop an aesthetic physique. However, simply adding chest exercises done at an incline isn’t good enough. If you really want that look, you have to concentrate on isolating upper pecs and not letting your shoulders do the work.
If you’re doing plenty of incline presses and incline flies, yet you still don’t seem to be isolating upper pecs like you’d like, chances are it’s because your shoulders are doing most of the work. The human body is naturally lazy, and likes to default to stronger muscles to make an activity easier. If you’re front delts are stronger than your upper pecs, then they’re the ones doing most of the work during your incline press and flies – not your pectoralis minor.
You know your front delts are bearing the brunt of the work if your shoulders are “shrugging” themselves forward while you lift. If you were isolating upper pecs as much as possible, then your shoulders would remain locked in line with your clavicles and torso as a whole. However, if you notice that instead of staying back, that they come forward as you press or fly, then your front delts have taken over from your upper pec.
The best way to go about isolating upper pecs is to radically reduce the weight. By doing this, you can improve your mind-muscle connection, and concentrate using perfect form. The main points to focus on will be keeping the shoulders locked back in their socket and feeling the pectoralis minor contracting.
However, just because you’re going light, that doesn’t mean you can’t get a good chest workout. Slowing the reps down quite a bit can ensure you not only work the muscle hard, but can actually help you improve that mind-muscle connection as mentioned above. Have the eccentric on each rep last 3-4 seconds, pause minimally at the bottom of the movement, take 2-3 seconds on the concentric, then squeeze the contraction hard for 1-2 seconds.
While you’re working with lighter weights, spend this time also perfecting your form. Try to keep your elbows as tucked as possible when doing incline barbell press instead of letting them flare out. When doing incline dumbbell flies, don’t let the thumb side of the dumbbells tilt higher than the pinky finger side, as this can shift emphasis to the delts, too. If you’re not sure about your form on some movements, either have a seasoned lifter watch you or film yourself to asses later.
One thing that you can borrow from the world of powerlifting would be to strengthen your rear delts and upper back. Many strength athletes have found that bench press performance stalls when they’re upper back is radically weaker than their chest. This doesn’t allow their shoulder girdle to be strong/healthy overall and often leads to unstable bench pressing.
If you’re suffering from a similar muscular imbalance, it could be a reason your front delts are taking over so easily. Your traps, rear delts, and upper back need to be strong enough to hold your shoulders in place while doing chest work. If they’re not, this could be a contributing reason to why your shoulders shrug forward and you’re having a hard time isolating upper pecs.
There are many things you could do to improve your upper back strength, but a simple one would be to start doing 50-100 reps of rear delt flies, face pulls, or banded pull aparts several days per week. These can be done as a part of your warmup, after your workout is over (it doesn’t matter what you’re training that day), or even as a separate “mini-workout”. The sets and reps aren’t as important here – just be sure you’re getting the volume in. A light resistance for 15+ reps at a time works great.
If you’re having trouble isolating upper pecs, give these tips a shot. Make sure you’re not suffering from muscular imbalances, but mainly emphasize proper form. Lighten the weight on your inclined chest exercises and focus hard on that mind-muscle connection. Ensure you’re targeting the pectoralis minor appropriately, and your upper chest development should rapidly improve.