How Thoracic Mobility Impacts Shoulder Range of Motion

Having adequate shoulder range of motion is crucial for being able to perform our daily activities. Whether we are reaching for the top shelf in the cupboard or competing in a baseball game, having full range of motion at the shoulder is essential (click here to see how shoulder flexion deficits may lead to elbow injuries in baseball pitchers). We often look to muscles surrounding the shoulder joint as the culprit to range of motion restrictions, but that approach alone may lead us to missing out some important clues that could help to explain these restrictions. One structure that may be worth exploring is the thoracic spine, as several studies have shown that a lack of mobility at the thoracic spine has the potential to restrict motion at the shoulder as well (1-4).

In 2005, Bullock and colleagues performed a simple study that demonstrated how thoracic mobility could impact shoulder flexion range of motion (1). In the study, participants would first assume a slouched posture before attempting to raise their arms overhead in the sagittal plane. They would then repeat this test with a more erect posture. The results were pretty eye opening. By simply sitting with a more erect posture, shoulder flexion increased by an average of almost 18 degrees! But why would a change at the thoracic spine have such a meaningful impact at the shoulder?


Functional Anatomy


An increase in thoracic kyphosis has the potential of leading to some negative functional changes in the upper quarter, at least in part due to its association with forward head posture as well as forward shoulder posture (2,4). Forward head posture is defined as a failure of the head to align with the vertical axis of the body. Forward head posture has been associated with a shortened levator scapulae and a decrease in serratus anterior activity while attempting to flex the shoulder (4). Because of the function of these muscles, both of these adaptations have a negative effect on the shoulder joint. The levator scapulae originates at the transverse processes of the upper cervical vertebrae and inserts at the superior medial border of the scapula. The levator scapulae serves as a scapular downward rotator so, when shortened, it has the potential to restrict upward rotation of the scapula. When we couple this with an inhibited serratus anterior, whose primary duty is to upwardly rotate the scapula, we are left with a scapula that is going to have a hard time upwardly rotating. This restriction in upward rotation limits forward flexion at the shoulder and can lead to impinging of the structures in the subacromial space.

As mentioned before, forward shoulder posture can also negatively impact shoulder flexion. Forward shoulder posture is defined as the acromion process being more anteriorly positioned compared with the mastoid and has been associated with a shortening of the anterior shoulder muscles, including the pectoralis minor (4). A shortening of the anterior musculature can lead to an anteriorly tilted scapula, which may lead to an imbalance in the scapular force couple that assists with upward rotation of the scapula (1,4). Once again, this leads to a loss of range of motion at the shoulder as well as a narrowing of the subacromial space, causing impingement of the structures in this space (1,4).


Assessing Thoracic Mobility


A simple way to assess thoracic mobility is to use Selective Functional Movement Assessment’s Lumbar Lock Extension/Rotation Test. First, have the individual start in the quadruped position. Next, have them sit their butt to their heels and drop their forearms down to the table, as shown in the video below. While blocking their shoulder and hip to prevent compensation, have the individual place the opposite hand behind their back and rotate that same shoulder towards the ceiling. Repeat the test passively to see if there are any discrepancies between active and passive range of motion.



In the general population, we are looking for about 50 degrees of thoracic extension/rotation while performing this test. In rotational athletes, we would like to see them achieve at least 70 degrees. If the individual is lacking motion actively but possesses full range of motion passively, we would deem this to be a neuromuscular control dysfunction. This means that the individual has range of motion available to them that they are unable to tap into. The video above shows a simple method for correcting these dysfunctions. If the individual lacks motion both actively and passively, however, we would attribute these limitations to either a tissue compliance dysfunction or a joint dynamics dysfunction. A tissue compliance dysfunction would imply muscle stiffness is leading to a restriction in range of motion. A joint dynamics dysfunction implies that the arthrokinematics of the joint are leading to these restrictions.


Corrective Exercise for Thoracic Mobility


For individuals who demonstrate restrictions in thoracic mobility, research has shown that a combination of joint mobilization and extension-based exercise can help to overcome these restrictions (3). This approach seeks to address dysfunctions for both the non-contractile tissues (joint dynamics dysfunction) as well as the contractile tissues (tissue compliance dysfunction). Using this approach not only aids in the restoration of shoulder flexion range of motion, it also has been shown to improve shoulder external rotation and internal rotation as well (3).


Below are some of my favorite exercises for improving thoracic extension:



Foam rolling is a great option for mobilizing the thoracic spine. Start by lying on your back with the foam roller resting in the middle of your shoulder blades. Next, give yourself a big hug in order to take slack out of the system then lift your hips off the ground and roll up and down 8-10 times (stay off of the lower back while performing this exercise). After rolling, drop your hips back to the ground and place your hands behind your neck. The purpose of this hand placement is to support the weight of the head; do not crank on the neck. While keeping your lower back in a neutral spine position, look up towards the ceiling in order to mobilize the thoracic spine into extension. Repeat this 8-10 times at segments that feel restricted.



The Bench T-Spine Mobilization, which I believe I stole from the crew at Cressey Sports Performance, is another great self-mobilization technique for the thoracic spine. Start in a kneeling position with your elbows resting on an elevated surface while holding a dowel. Sit your butt towards your heels, drop your chest towards the ground, and curl your hands behind your head. Exhale at the bottom prior to returning to the starting position. Repeat this exercise 8-10 times.



The Kettle Bell Rotation and Press can be used to improve tissue compliance of the trunk flexors to allow for greater trunk extension. Start by lying on your side with your knees bent to hip height. Use your bottom arm to stabilize your top leg and use the top arm to hold a kettle bell in an arm bar position. Rotate the kettle bell towards your top shoulder and rotate your top shoulder towards the ground. Be sure to keep your elbow in tight as if you were squeezing a newspaper against your side while performing this motion. Exhale at the bottom before returning to the starting position. Repeat for 8-10 repetitions.



After increasing range of motion passively, we need to teach our body how to control this newly acquired motion. The Half Kneeling Resisted Open Book is a great exercise for teaching thoracic rotation neuromuscular control. Start in a half kneeling position with your inside knee down. Pin a yoga block against the wall with your front knee to ensure your pelvis does not move while performing this exercise. While holding a band with your palms up and elbows straight, rotate your outside arm open while following the hand with your eyes. Exhale at the end prior to returning to the starting position. Repeat for 8-10 repetitions.



The 135 Degree Wall Slide with Lift Off is a great way to target the thoracic extensors as well as engaging the lower trapezius for improved posterior tilting of the scapula. Learning to posteriorly tilt the scapula is extremely important for being able to achieve full shoulder flexion, especially in those individuals with a “short” pectoralis minor muscle. Start in a split stance position with your pinkies on the wall. Slide up the wall to form the letter “Y” with your arms before lifting your arms off by about an inch. Hold this position for 3-5 seconds before returning to the starting position. Repeat this exercise 8-10 times.



The Waiter’s Carry is a great exercise for teaching shoulder flexion neuromuscular control while maintaining an erect posture. While holding a dumbbell or kettle bell overhead in one arm, walk for 30-60 seconds while maintaining your upright posture. Repeat the exercise on the opposite arm.


Summary


Possessing adequate shoulder flexion range of motion is not only necessary for activities of daily living, but it can be beneficial for overall shoulder health as well. While we often look to muscles around the shoulder joint for answers for range of motion restrictions, the thoracic spine also plays an important role. Increased thoracic kyphosis can lead to negative adaptations that decrease shoulder function and limit our ability to get overhead. By increasing thoracic mobility through joint mobilizations and extension-based exercise, we have the ability to improve shoulder range of motion as well as shoulder health.



Resources


1. Bullock MP, Foster NE, Wright CC. Shoulder impingement: the effect of sitting posture on shoulder pain and range of motion. Man Ther. 2005 Feb;10(1):28-37

2. Hunter DJ, Rivett DA, McKeirnan S, Smith L, Snodgrass SJ. Relationship Between Shoulder Impingement Syndrome and Thoracic Posture. Phys Ther. 2020 Apr 17;100(4):677-686.

3. Park SJ, Kim SH, Kim SH. Effects of Thoracic Mobilization and Extension Exercise on Thoracic Alignment and Shoulder Function in Patients with Subacromial Impingement Syndrome: A Randomized Controlled Pilot Study. Healthcare (Basel). 2020 Sep 2;8(3):316

4. Singla, D., & Veqar, Z. (2017). Association Between Forward Head, Rounded Shoulders, and Increased Thoracic Kyphosis: A Review of the Literature. Journal of chiropractic medicine, 16(3), 220–229.