There are three main joints that are stressed when playing golf. These include the wrist, the elbow, and the shoulder. Although both the knees, as well as the hip, are often moved (see pictures 5-8), these joints are not quite as important and no injuries usually occur in these areas. Power is definitely gained from their movement though. Another area that is involved with movement is the trunk. Though technically not a joint, it is extremely important in the golf swing, and is an area where injuries do occur. The following descriptions are for a left handed golfer. Although more rare, I am one of them, so it’s easier for me to explain
Wrist
The wrist joint is a condyloid articulation, and more generally a synovial joint, and is very important in the game of golf. This means it is bathed in synovial fluid, allowing a great deal of mobility. At the beginning of the stroke, the wrists are pointed downwards slightly. They will be flexed upwards by the top of the backstroke, bent down again at contact, then up again at the top of the follow-through.
Elbow
The elbow is a hinge joint, so although it cannot move side to side, its stability is key to golf. The left elbow will be bent throughout the stroke. It will conform to the movements of the right elbow, and may be slightly more bent or straighter at different times. The right elbow, however, will be kept straight throughout the golf wing, until the follow-through, when it will bend as the club turns around the body.
Shoulder
The shoulder, or glenohumeral joint, is a synovial joint, and more specifically a ball and socket joint. Both shoulders twist to left and up during the backswing, then right and down during the downswing. The shoulders finish off the follow-through by turning up and to the right.
Muscles and Bones
There are about 22 muscles that are used to power the golf’s downswing. The descriptions are again for a golfer that shoots left. Hip
The gluteus maximus,