Shoulder pain that occurs during or after throwing is a widespread problem, particularly among overhead athletes such as baseball players, softball pitchers, and javelin throwers. The repetitive, high-velocity nature of the throwing motion places tremendous forces on the shoulder joint’s delicate structure. This joint must be mobile yet stable enough to withstand forces that can exceed the athlete’s body weight. Ignoring pain in the throwing arm is never advisable, as it often signals microtrauma that can quickly progress into a severe structural injury.
Identifying the Specific Injuries
Pain while throwing often originates from damage to soft tissues responsible for joint stability and movement. A common issue involves the rotator cuff—four muscles and their tendons that keep the upper arm bone centered in the shoulder socket. Repetitive throwing can lead to tendinopathy (inflammation and irritation) or partial-thickness tears, most often affecting the supraspinatus tendon. These injuries result from the extreme eccentric load the rotator cuff must absorb to rapidly slow the arm down after the ball is released.
Another source of deep shoulder pain is a Superior Labrum Anterior to Posterior (SLAP) tear. This injury affects the labrum, the ring of cartilage that deepens the shoulder socket, specifically where the long head of the biceps tendon attaches. The mechanism for a SLAP tear involves a “peel-back” effect, where the biceps tendon pulls the labrum away from the socket during the late cocking phase when the arm is rotated maximally backward.
Biceps tendinitis, inflammation of the upper biceps tendon, causes pain localized to the front of the shoulder. This condition often occurs alongside internal impingement, sometimes called “The Thrower’s Shoulder,” where the rotator cuff tendons at the back of the shoulder get painfully pinched between the humeral head and the glenoid socket during the cocking phase. This continuous pinching can lead to partial rotator cuff tears or damage to the posterior labrum.
Understanding the Biomechanical Faults
Structural damage is often the consequence of faulty movement patterns and adaptations to the high demands of throwing. A common adaptation is Glenohumeral Internal Rotation Deficit (GIRD), where the throwing arm loses internal rotation compared to the non-throwing arm. This loss is caused by a tightening of the posterior capsule and rotator cuff, which shifts rotational stresses forward, placing increased strain on the anterior structures and labrum.
Another fault is Scapular Dyskinesis, which involves visible alterations in the position and movement of the shoulder blade (scapula). The scapula acts as the foundation for the shoulder joint. Poor control from weak stabilizing muscles (like the serratus anterior and trapezius) disrupts the entire kinetic chain. This instability prevents the shoulder blade from correctly upwardly rotating, which reduces the space for the rotator cuff tendons and contributes to impingement.
Improper timing within the throwing motion increases the forces placed on the joint. The late cocking and deceleration phases are the two most demanding periods for the shoulder. Errors in transferring energy from the lower body and core force the smaller shoulder muscles to work harder, leading to fatigue and breakdown. When the arm lags behind the trunk rotation during the late cocking phase, the resulting hyper-external rotation can exacerbate GIRD and internal impingement pathologies.
Immediate Management and Warning Signs
When acute shoulder pain strikes during a throwing session, stop the activity immediately to prevent further trauma. Initial management involves the principles of Rest, Ice, Compression, and Elevation (RICE), though compression and elevation are less relevant for the shoulder. Applying ice packs to the painful area for 20 minutes several times a day helps reduce inflammation and manage pain.
Over-the-counter Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), such as ibuprofen or naproxen, control pain and swelling in the short term. However, this should be a temporary measure, as masking pain can lead to an athlete returning before the underlying injury has healed. If the pain persists for more than a few days despite rest, a professional evaluation is necessary.
Certain symptoms act as “red flags” and require immediate medical attention, signaling a severe injury. These include sudden, sharp pain accompanied by a distinct popping or snapping sound. Other warning signs are the inability to lift the arm, a noticeable loss of strength (indicating a complete tear or nerve damage), numbness or tingling radiating down the arm, or a visible deformity of the shoulder joint.
Strategies for Injury Prevention
Prevention focuses on establishing a strong, stable foundation for the high demands of the throwing motion. Specific strengthening exercises targeting the posterior rotator cuff muscles (such as the infraspinatus and teres minor) are important for safely decelerating the arm. Strengthening the scapular stabilizers, including the middle and lower trapezius and the serratus anterior, ensures the shoulder blade provides a stable base. Exercises like prone T raises and resistance band external rotations are effective for isolating these muscle groups.
Flexibility work is important, especially addressing the tightness associated with GIRD through posterior capsule stretching. Incorporating stretches that restore internal rotation helps maintain the total arc of motion, reducing strain on the anterior joint structures. A proper warm-up routine before throwing prepares the tissues for high-velocity movement.
Managing workload is a protective strategy, especially adhering to established pitch count and rest day guidelines. Throwing while fatigued increases the risk of injury significantly. Ensuring adequate rest between throwing sessions allows the body time to recover from the microtrauma that occurs during high-intensity activity.