The lower trapezius muscle plays an important role in moving and positioning the shoulder blade (scapula) during overhead sports. The lower trapezius spans from the lower 6 thoracic spine vertebrae to the upper portion of the scapula. Along with the middle and upper portions, the lower fibers comprise the large trapezius muscle of the upper back. The lower trapezius, upper trapezius, and serratus anterior muscles work together to upwardly rotate the scapula. This function is important to optimally position the arm during overhead function such as the cocking phase of throwing a baseball. This muscle is often ignored when it comes to developing resistance training programs for athletes or fitness enthusiasts.
Role of the Lower Trapezius in Sport
Poor thoracic spine posture or loss of thoracic spine extension places the lower trapezius at a disadvantage to fulfill its role as a scapular stabilizer. Therefore, exercises which restore thoracic extension are often included in programs which train the lower trapezius. Delayed lower trapezius activation has been demonstrated in overhead athletes with shoulder pain. Weakness of this muscle has been implicated with upper extremity injuries in baseball, swimming, and tennis.
Exercises performed with the arms below shoulder level elicit very little lower trapezius activity. In order to optimally activate the lower fibers of the trapezius, movements which facilitate scapular upward rotation with depression should be performed. The lower fibers are aligned at an approximate 135-degree angle from the spine. This corresponds to the 10:00 and 2:00 positions on a clock. Exercises such as the wall slide, prone trapezius raise, and shoulder external rotation in 90 degrees of abduction position the scapula for optimal lower trapezius activation.
Prone 1-Arm Lower Trapezius Raise
This exercise is performed lying face down with one arm over the side of the table or bench. Be sure to keep the neck in a relaxed neutral position resting on your other forearm. With the thumb up, arm straight, elbow slightly bent, lift toward the ceiling at a 45-degree angle from your head (the 10:00 and 2:00 positions of a clock). This position is aligned with the muscle fibers of the lower trapezius. Be careful to avoid shrugging the entire shoulder as you raise the arm. Instead, think about tilting the shoulder blade backward as you raise the arm. Pause at the top of the movement before returning to the start position in a controlled manner.
Prone External Rotation in 90 Degrees of Abduction
Lie face down with one arm over the side of the table or bench supported on a small towel roll. Be sure to keep the neck in a relaxed neutral position resting on your other forearm. Rotate the hand up towards the sky in a slow and controlled manner. Be careful to avoid shrugging the entire shoulder as you perform the exercise. Pause at the top of the movement before returning to the start position.
Wall Slides at 135 Degrees with Lift Off
Stand to face a wall with one foot slightly ahead of the other. Place both forearms against the wall starting just below shoulder level. Initiate the movement by sliding the forearms toward the ceiling at a 45-degree angle from your head (the 10:00 and 2:00 positions of a clock). This aligns with the muscle fibers of the lower trapezius. Once the elbows are fully extended, slightly lift the hands and arms away from the wall. Be sure to avoid arching the low back as you lift away. Instead, think about tilting the shoulder blades backward as you lift away. Pause at the top of the movement before returning to the start position in a controlled manner.
The lower trapezius muscle is often ignored by athletes and exercise enthusiasts who regularly engage in strength training. Poor timing or weakness of this muscle results in compensatory movement patterns during overhead activity. Specific exercise targeting the lower trapezius should be included as part of a warm-up routine or regular strength and conditioning program for athletes looking to optimize shoulder health.