The solution is simple. Focus on the less developed and smaller side of the muscle. For example, the same biceps, if your left arm is relatively large and your right arm is relatively small, then you should do more groups on the right side, and the left side can appropriately reduce the training amount, so that the muscles on both sides can develop symmetrically and synchronously. When your muscles are symmetrical, you should also pay attention in future training. For example, if you do 10 group on your left biceps, you will be exhausted, and if you do 8 groups on your right side, you may be exhausted, so exercise must be based on the weak side. When the weak side is exhausted, you should end the training even if the strong side still has spare capacity.