I would wager that people who strength train are universally aware of the upper trapezius muscles. When developed, these are the impressive-looking neck muscles that shrug the shoulders. The “traps” do not end at the shoulders. The trapezius muscles continue down the spine, transitioning from the middle trapezius to the lower fibers ending just above the lower back.
What function does the lower trapezius serve?
The lower fibers are referred to as the lower trapezius, and are responsible for helping rotate the shoulder blade upward as well as drawing the shoulder blades down. They may also play a role in tilting and rotating the shoulder blade when reaching overhead.1 When the lower trapezius functions “properly,” this may decrease the risk associated with shoulder impingement.2
Is this muscle being addressed in your conditioning program?
A study that investigated a group of bodybuilders found that this population has proportionally weaker lower trapezius muscles.3 I find it rare when any individual has good strength of this muscle.
Why They May be Neglected
Issue 1 The weight trainer may not be focusing enough on the muscles of the back. The lower trapezius can be activated during exercises such as the pull-down and row. Specific exercises for the lower trapezius may also not be incorporated in the training program.
If these exercises are ignored, particularly in favor of chest, “trap,” and anterior deltoid exercises, strength deficits in the lower trapezius can occur.
Issue 2 The weight trainer may not be performing exercises such as cable rows in a way that effectively targets the lower trapezius. Although these movements are traditionally used to train the latissimus and rhomboid muscles, upper trap involvement may be proportionately high and lower trap involvement low.
Begin using exercises that help activate the lower trapezius.4
The following exercise should be performed with little or no weight. As the exercise becomes more rigorous more upper trap activity occurs.5 There is nothing wrong with going heavier, but lower trap involvement decreases in relation to the other scapular musculature.6
This exercise can be performed on the side of a bed, bench treatment table, etc.. To perform the exercise, lift the arm from a hanging position with the thumb up. Both arms may be raised to form a Y. It is common to perform these for repetitions or for static holds.
Modified Prone Cobra
Retract the shoulder blades and draw them down while lifting the chest off the floor. Rotate the arm out and down at the shoulder. Although not depicted in the picture, rotating the arm so the thumbs are up may help ensure that the humerus (upper arm bone) is rotated appropriately. Ten repetitions with 10-second holds should be sufficient in most cases.7
Ensure rows and other back exercises do not have an upper trap emphasis.
When rowing or performing other pulling exercises be sure to draw the scapula down and in during the exercise motion.5 This is how I recommend performing most back exercises to engage the lower trapezius. Be mindful not to shrug the shoulders up while pulling.8 Sometimes, particularly during heavy training, the upper trapezius may come into play, taking focus away from the lower trapezius.
Those who weight train may have a proportionally weaker lower trapezius, which may be associated with issues such as shoulder impingement. I have described simple exercises that may help the strength trainer ensure these muscles are being stimulated. Ensuring there is not excessive upper trap emphasis during pulling exercises may also help ensure the lower trapezius are being sufficiently worked in relation to the upper trapezius.