Shoulder transverse extension is a lateral movement at the shoulder (glenohumeral) joint in a horizontal plane, resulting in an increase of angle (extension) – moving the upper arm away from the chest with the elbow out to the side – see Figure 1.
In anatomical terminology, a lateral movement is one that moves part of the body further from (lateral to) the midline of the body.
The key muscle involved in this movement is the posterior deltoid. The latissimus dorsi. The infraspinatus and teres minor also play a weak role.
You May Also Like…
Internal and External Rotation of the Arms in the Golf Swing
Introduction to the Swing like a Champion System.
Overview of a Great Golf Swing which summarises the correct movements in a great golf swing.
Golf Anatomy and Kinesiology, a collection of articles describing the roles of the muscles involved in the golf swing.
The Role of the Deltoids in the Golf Swing
The Role of the Latissimus Dorsi Muscle in the Golf Swing
The Role of the Teres Minor in the Golf Swing