Strong Shoulders, Strong Serve: The Story Behind Your Shoulders

Written By: Dr. Carla Cupido

Tennis players run a high risk of shoulder injury due to the repetitive and extremely dynamic nature of the sport.  However, a combination of the following can significantly decrease the threat of injuring your shoulders, while improving strength, power, and endurance:

  1. strong shoulder blade stabilizers;
  2. correct movement patterns (a.k.a. team work), and
  3. mid-back mobility.

Think of the muscles and joints in your body like a doubles team; if both teammates bring the same level of talent to the court and play cohesively, games are won, but if one is weaker than the other and they play out of synch, games are lost. The point: if both teammates are equal in ability and play well together, one doesn’t have to make up for the other’s weak performance, or in body talk, one area of the body doesn’t have to compensate for another’s weakness or inflexibility.

Anatomy You Should Know


The scapula, also known as the shoulder blade, is a very important anchor point in the body.  It houses the head of our arm bone; it constitutes half of our shoulder joint; and it is the attachment site for our rotator cuff muscles, several arm muscles and our scapular stabilizers.

Rotator Cuff Muscles

The rotator cuff comprises four muscles (supraspinatus, infraspinatus, subscapularis and teres minor) whose function together is to secure the head of the arm bone (ball) in the socket (which is part of the shoulder blade).

Scapular Stabilizers

Scapular stabilizers (middle and lower trapezius, rhomboids, serratus anterior) are muscles that stabilize and attach your shoulder blade to your skeleton and are commonly neglected in training.  They work as a team to ward off that chicken wing look that you won’t see on any elite tennis player. Without these muscles, your shoulder blade would only attach to your skeleton via one tiny joint (acromioclavicular, or AC, joint), which could never withstand the forces of your powerful serve. This means that your muscles must do the rest of the work at anchoring the shoulder blade to your body.

That old song holds true: “the shoulder bone’s connected to the arm bone”; however, when we learned that song as children, we didn’t learn the muscles that connected one bone to the next and their significance in preventing injury and improving performance.

Take home point: If the scapular stabilizers are not strong, the shoulder blade will sit lazily on the spine. This means that no matter how strong the rotator cuff muscles are, weak scapular stabilizers will prevent the possibility of the arm bone being harnessed securely in the socket… protecting the shoulder joint and improving shoulder power.

Team Work

“Packing the shoulder” refers to engaging the scapular stabilizers and appropriately positioning your arm bone in the socket, which means, pulling your shoulder blades downwards away from your ears and drawing them inwards towards each other on your back. This is harder than people may think. It often takes a significant amount of time and cuing to be able to get patients to perfect this pattern. They often can’t tell when they are doing it incorrectly at the start. When this is correct, more power can be transferred from the core of the body to your racquet as well, so not only are you improving your game, you are taking some risk of injury out of the equation.

Mid-Back Mobility

When the mid-back lacks mobility, the shoulder blades tend to become more mobile to make up for the mid-back’s restrictions. This, as you have learned, will then make the shoulder joint more prone to injury, as the shoulder blade is not anchored firmly by those scapular stabilizer muscles. Therefore, the mid-back is just as important to shoulder health as the scapular stabilizers are.
The mid-back can be restricted due to many factors, but our sedentary work or school days tend to be the number one culprit. Muscles and joints work together which means that often if muscles are tight, joints become restricted in their movement. Improving the function of both is very important. Seeking the care of a manual health practitioner can help improve the mobility of this area of the body and provide you with exercises that you can do on your own.


Prescription for strengthening and lengthening exercises should be specific to each person’s current state of fitness and their tennis goals.  However, whether you are setting out to rally with a friend once a month or compete internationally one day, you will need strength and endurance from your scapular stabilizers as well as your rotator cuffs. A manual practitioner (chiropractor, physiotherapist, sports MD) can help you identify which muscles need addressing with respect to strength and flexibility.

Stay tuned for a future blog offering some excellent exercises to help take your game to the next level.