True the shape of a muscle can't be changed with any method of exercise. To the very extreme, surgery would be probably the only option with regards to muscle inserts, length, etc. Another examples might be a high bicep peak.......just something your born with. All the hours of direct bicep work , if born with a longer & flatter bicep head, will never make a difference. In any case, the full potential of any muscle can most always be reached.
Might try a different slant of pec/chest training...exploring the possibilities. Might suggest dips, with the knuckles facing forward. Another version would be with the knuckles facing inward, though would not advise this way for most folks...needs caution at first where learning the proper way.. Either of these methods are best preformed on a "V" bar, which can allow a adjustable or wider hand spacing than on normal dipping bars. These are just not Gironda's style, but other old timers have also done these . But well worth the effort to do a search of Gironda's training styles.
Pec Decks (if your lucky enough to have a nautilus machine..all the better) work very well. Want the one's that place the elbows on the pads, rather than having the arms stretch way out. More resistance is placed on the pec's themselves that way (want the elbows to lead the way...like in most other exercises). Have the elbows raised inline with the shoulder level, nothing lower..please.
DB Pullover & Press. DB's, rather than a BB, tend to reduce any possible stress on the wrist and elbows...but you will have to make up your own mind about that. I have used both version with great results.
Good Luck
