i thickened up my pecs after decades of training by taking the triceps and delts out of the picture.
Pec Deck. but you don't press with your elbows and forearms, i don't feel shit when i do that.
grab the bottom of the pads with your hands, flare your elbows out, and DON"T make a wide swinging motion like you normally would. keep the motion tight, the pads should never be more than a few inches in front of your chest. and just "open and close" the machine. it should be linear, not circular. Elbows out and squeeze. think more that you're pulling the handles in with your pecs, than pushing them with your arms
And I move the seat up and down....and grab different parts of the pads to hit upper and lower.
My theory is that Bad body parts are bad because biomechanically, you are set up where it's hard to get a good "feel" for them, you lose tension on the muscle, or dominant muscles take the workload.
what I try and do is figure out ways around it.
