There are some trainers/gurus/science-geeks that say you cannot do a thing about the shape of your muscles, as this is 100% genetically determined. Others believe that by “targeting” certain areas of a muscle, you can in fact, change its shape.
While I do not believe we can change the actual genetic “map” we have been provided for each of our body parts, I do believe that we can utilize specific exercises, angles, and grips to bring out the full potential of each muscle.
In other words, when someone is lacking upper chest development, I do not necessarily feel that it’s simply because genetics is “dictating” that the lower pecs dominate the upper, but rather that the upper pectorals are not receiving the proper stimulation in order for it to grow to its maximum potential.
Yes, it is true that you cannot completely isolate one area of a muscle from another no matter what exercise you utilize. However, you can affect certain groups of motor units more than others in a single muscle by using specific grips and/or planes of motion (as EMG studies have proven) This can then lead to accelerated growth in a particular “head” or section of a complex muscle.
It is interesting to note that there are certain common “flaws” that seem to appear over and over again amongst so many trainees. I do not feel this is always a result of a genetic limitation, but rather a function of unbalanced training.
So before you take the easy way out and blame faulty genetics for your disproportionate physique, make sure you are doing everything possible training-wise to address the problem. In other words, the genetics might be there, but many are simply failing to actualize the full potential of each individual muscle group.
With that in mind, here are my 8 favorite (rarely utilized) “muscle-shaping” movements: