Why Does My Shoulder Hurt When I Throw a Ball?

The Mechanics of the Throwing Shoulder

The shoulder is a ball-and-socket joint that allows a wide range of motion. Because of its flexibility, it is not as stable and needs other structures for support. These structures are a collection of four muscles known as the rotator cuff and a ring of cartilage known as the labrum.

During a throw, the shoulder moves through extreme external rotation, then into strong internal rotation, and finally into a slowing-down phase. If any phase does not function properly, then there is added stress on the shoulder joint, which could result in injury.

Common Causes of Throwing Pain

The most common reasons for shoulder pain while throwing a ball are:

Rotator Cuff Tendonitis or Tears

The rotator cuff muscles work intensively to keep the bone in the socket during the fast throw. Overuse can result in inflammation (tendonitis) or small tears in the tissue. It may feel like a dull ache that hurts during the cocking part of the throw.

Shoulder Impingement

Impingement is where the top of the shoulder blade (acromion) digs into or pinches the rotator cuff tendons that are underneath it. This is common in athletes who make use of overhead movements. You may feel sharp pain at the peak of the throwing motion.

Labral Tears (SLAP Tears)

The labrum is a cushion that helps hold the bone in place. A SLAP tear can occur in throwers as a result of repetitive stress during the late cocking phase. This leads to a deep ache with a sensation of catching or popping.

GIRD (Glenohumeral Internal Rotation Deficit)

Frequent throwing can cause tightness in the back of the shoulder over time. This reduces your ability to rotate your arm inward, which changes how the joint moves. As a result, extra stress is placed on the front of the shoulder, increasing the risk of injuries to the labrum and rotator cuff.

When Should You See a Specialist?

Not all shoulder soreness means injury. It is normal to feel muscle soreness after heavy throwing. However, you should see a specialist if you notice:

• Pain that continues even after a few days of rest
• A drop in throwing speed or a dead arm feeling
• Pain that travels down your arm or into your neck
• Night pain that makes it hard to sleep on that side