First of all, you should understand that the strength of each person's right hand and left hand is different, so in the process of practice, the arm with good strength has a better shape, while the other arm is unable to bear the strength you have practiced. Natural muscles are deformed. Generally, you should pay attention to the poor strength of that shoulder when practicing, so you subconsciously let this shoulder train.

I work out. What don't you understand? You are asking.