^THIS^
I dont agree.
When I flat bench, my shoulders and tri's take over tremendously, I barely feel any pump in my chest whatsoever.
When I tried decline benching (after Dorian recommended it for this reason), I found my entire chest gets a gnarly pump and I feel a lot less in my shoulders and tris.
I tested this very scientifically.
I loaded a light weight I could pump out on the bar with ease (135), and pumped out reps until I could feel the muscles swell with blood.
I did one excercise to begin my chest workout one week, and the other the following week.
Pumping with the flat bench caused me to feel pumped in the shoulders/tris much more.
The decline made the whole pec feel pumped in a way I have never felt before, Ive always struggled at getting my pecs involved on benching movements. I also did this test back to back one week, flat first, decline second, with the same result.
Barely felt it work the pecs with flat, DESTROYED the pec with decline.
IMHO Dorian was exactly correct, the function of the pec is to pull the arm forward and across the chest, and the decline does that perfectly IMHO. I tossed out flat bench entirely, replaced with decline.
A lot nicer to feel like youre actually working the muscle youre targeting, instead of just moving weight cause its the "flat bench"