Your rotator cuff muscles are the foundation of your shoulders. These small muscles are classified as your synergists or stabilizers that come into play whenever your work any major upper body muscle group. So it goes without saying that these are just as important when constructing a training program. Simply put, if you want to get stronger in the bench press, do rotator cuff work. If you want to be able to perform a chin-up, do rotator cuff work as well. They may not be able to give you the kind of satisfaction or muscle pump you need, but long term they will definitely guarantee you healthy shoulders.