On a lot of pressing movements, one of the cues that I’ve seen a lot of back and forth on is to squeeze your shoulder blades back when pressing. Some call it “cheating” while others, like myself, feel it’s a great strategy for improving growth.
One of the reasons It gets a bad rap is because when people think of pinching your shoulder blades back, they think of strength athletes who, in effect, decrease the range of motion for a competition qualifying bench press. It also helps strength athletes keep their spine in a neutral position, increasing the total load that can be lifted. In bodybuilding we are looking to maximize the tension through the full range of motion. If bodybuilders were to train this way, we would be in effecting “cheating ourselves”.
So, we aren't talking about a crazy back arch like strength athletes. Then, what are the benefits of pinching our shoulder blades back on a chest press for optimizing muscle growth?
The main benefit for pinching your shoulder blades for muscle growth are to pre-stretch the chest. If you’ve followed my posts for long enough, you’ll know that I’m a big proponent of maximizing the stretch position on all of our lifts. The stretch position has been shown over the years to be where the best growth seems to comes from. So pre-stretching muscles where it makes sense, is a useful tool for maximizing growth.
Try this:
Stand up and lift both arms out in front of you
Pull your shoulders back and pinch your shoulder blades, keeping your arms in front of you.
This is the kind of scapular retraction (should blade pinching) that we are talking about.
Check out this video demonstration for a step-by-step guide on performing a chest press using this method.
I think the old "try to squeeze a pencil between your shoulder blades" cue makes people over emphasize the pinch and makes pressing a bit awkward, but the cue that really worked for me is the idea that I should be "reaching" my chest to the sky at the bottom. Made for a much more natural feeling arch and a great stretch, which as you mention is the whole point
A lot of people mention that always arching is bad for your "natural rhythm" of your scapula and maybe they have a point but the antidote to that is to just do pushups with protraction at the end every now and then