I agree with roboe that with heavy wights it is easier to generate large fiber recruitment than with all those tiny detailed exercises. Otherwise Anybody could get big arms just from just doing triceps kickbacks and biceps concentration curls !!!
However these exercises still can be used by advanced guys as they have developed the neural pathways and mental hardness to force moving a relatively heavy weight in an exercise without the possibillity of cheating or using momentum/acceleration.
But I still maintain that angles and insertion points of the muscles can make a difference. Most noticable , SQUATING gives me larger upper frontal and outer quads while leg pressing (i use much heavier weight than with squating) tend to localize development the teardrops near the knee. Mind you, if the weight and the reps are intens enough the frontal/outer quads kick in to some degree. But not enough to render serious growth in that area (in my case)
I think that for muscles that run parralel like bi's and tris it is much more difficult to make the inner or outer head grow ahead of the outer. Exercises that seem to focus on speciffically the inner or outer head typically are exercises that require lighter weight (so probably less fiber recruitment, maybe ok for the advanced bb)
However chest, the muscles do not insert a various points so i feel that hitting pecs with different angles does make a difference. Again this will only work if you use the heavy weights (Robboe is right all the way here) and watch out not to put all your enrgy in cable crosses and incline flies. I think the incline dumbell press (at 30 and 35 degrees) has got to be the best overall pec exercise as it complies to three important rules:
- full range of motion
- heavy weight
- specific (you can target the upper pecs from desired angle)
Now about the full range of motion. Why do we need that anyway? If we follow Robboes filosofy about doing just the heavy basics for overall development than why not do only partial reps barbell curls?
Again the answer lies in the fact that only andvanced guys have developed the neaural pathways to recruit more fibers using isolation/partial movements
Did you know good old sege nubret could develope his upper and lower chest just doing 20 sets of barbell benchpresses in a workout , eventhough his upper chest clearly inserted at different angle...
Well again it is neural pathways, Subconsciously he could contract his upper pecs to a large extend as well while doing the exercise. Unfortunately most of us are not like nubret so we have to do some angled work to force pathways to develope....