Seventeen (yes, seventeen!) different muscles are involved in shoulder motion. For golfers, some of the most important muscles are:

• The rotator cuff muscles
• The pectoral muscles ("pecs"), strong muscles that form the main part of the chest
• The latissimus muscles ("lats"), which along with the pectoral muscles, provide power to the golf swing

Contrary to popular belief that the left shoulder muscles provide most of the "drive" to the golf swing, research has shown that muscles from both shoulders are equally active (and therefore equally important) in powering the golf swing.