One of the most important muscle groups to exercise if you are into weight training are the shoulders. The shoulders will be involved in some way on every weight lifting exercise you do for the upper body. The shoulders are the link between the arms and the rest of the body, and you will have to use your arms whenever you train the upper body muscles. You will also want to build strength and size in the shoulder muscles themselves. Since they are involved in so any exercises you will have to be careful about over training the shoulders so they are constantly sore or injured. One of the top shoulder workout tips is to do most of your training focusing on the side heads of the muscles. Building the side shoulders will lead to a wider upper body.