Bottom line: everyone should experiment for themselves with all possible variations and come to their own conclusions.
First I want to say that I agree with the parameters of 8-12 reps and staying away from maximal lifting till the age of 17+.
Now, Pumpster, you make it look like I'm simply arrogant and above being wrong and this is simply not true. I am not convinced of my opinion, I am convinced of facts and truisms and one of those being that you cannot seperate the pec major into sections. You can put more emphasis on it by taking away the delts and triceps in the decline position and that is something that is taught in a basic applied anatomy class.
You're right on a few accounts that most of exercise physiology has been discovered by experimentation and it's only recently that science has been able to prove or disprove certain claims. Will decline work the chest more? Sure because you do not have as many synergists in the equation but my point was it does not isolate the muscle. In order to truly change the shape of a muscle you would have to move the insertion points. So, the truth and not my opinion is you cannot do decline this or that at the seclusion of any part of the pec muscle, it's an all or none hit. Will doing flyes cause a different stress on the muscle than benching? Sure. This is mainly due to the flying motion being the pec's greatest movement of strength-adduction.
I am hardly the last word and always willing to admit when I'm wrong, please do not make me out to be someone who thinks they are on a pedestal. The truth is there are a great many of people that know far more than I do; I'm simply making my way through exercise phys knowledge as much as anyone else is.
You're spreading this out of the original post. When you bring in muscle groups that are comprised of different heads and those heads may be fast or slow twitch dominant, then you're bringing something different and yes...different movements are needed to ensure a proper full "hit." The example being the triceps needs two different types of movement to hit the three different heads, one being an overhead extension. The same with the biceps, certain movements will stress certain heads more than others, some movements will work the brachioradialis and some will not, etc. The same can be seen with the calf, the soleus being one twitch fiber and the gastrocenemius being another twitch fiber, so they each need different angles and parameters.
However, while yes you can cause a different stress to the pec major by different angles and different movements, you cannot hit the lower portion of the pecs without hitting the upper portion of the pec and that is fact, not my opinion. The pec has no heads, one origin and a couple of insertions. The entire muscle fires and a complete contraction happens, not a localized one.
So, while I agree with you on most of your points, I disagree on some.
