Which muscle action does the trapezius NOT perform?

The trapezius muscle is primarily involved in stabilizing and moving the scapula (shoulder blade) and is associated with several specific actions. It plays a significant role in raising the shoulder, rotating the scapula, and retracting the scapula. Each of these functions reflects the trapezius's involvement in movements related to positioning and stabilizing the shoulders and upper back.

When it comes to extending the arm, this motion is primarily facilitated by other muscles such as the latissimus dorsi and deltoid, specifically the posterior part of the deltoid. The trapezius does not directly contribute to the action of extending the arm, which involves moving the arm backward at the shoulder joint. Therefore, this action is not attributed to the trapezius, making it the correct response in this context.

Understanding the functions of different muscles is essential in physical education as it allows for a better grasp of biomechanics and how various movements are performed during physical activities and sports.