The Importance of Scapular Stability for Healthy Shoulder Mobility

In the human body, the shoulder is the most mobile joint and the most susceptible to injury. This ball-and-socket joint is made up of the scapula (shoulder blade) and the head of the humerus (arm bone). The scapula contains the glenoid fossa, which is the socket of the shoulder. When the arm moves, the scapula also moves to position the glenoid to assist in shoulder movement. Because the scapula has no bony articulations, muscles attached to the scapula are responsible for its movement and its stabilization. Scapular muscles contract in coordination with the rotator cuff to anchor the scapula and move the shoulder efficiently. Consequently, imbalances and/or weakness of the scapular musculature can result in shoulder dysfunction and lead to injury. Resistance exercises can be done to strengthen the scapular muscles and reduce the risk of injury.

The main stabilizers of the scapula are levator scapulae, rhomboids major and minor, serratus anterior, and trapezii. These muscles can be strengthened through exercises using resistance as well as body weight.

Some examples of exercises are shown below:

D1 flexion/extension and D2 flexion/extension are proprioceptive neuromuscular facilitation (PNF) diagonal patterns that mimic functional movements of the shoulder joint.


The prone I, T, and Y exercises target the main stabilizers of the scapula. These exercises are begun lying face down with the arms hanging freely. The arms are then brought up as shown in the pictures below, with an emphasis on squeezing the shoulder blades together.

Shoulder injuries typically occur when the muscles of the shoulder girdle are fatigued. For this reason, these exercises should be performed for 2–3 sets of 10–15 repetitions in order to increase muscular endurance in the shoulder girdle.

The muscles of the shoulder work in coordination with the scapular muscles for proper functioning of the shoulder joint. If scapular muscles are not balanced or strong enough, shoulder injury can result. PNF patterns and prone I, T, and Y exercises can aid in the recovery and prevention of a shoulder injury. Try these exercises at home or visit a Sports PT of NY office if you feel that you may suffer from weak scapular muscles!