Jim Moran, PT, Shoulder Specialist

The baseball season is in full swing and many players are facing the frustrating characteristics of “Dead Arm.” A month ago you were throwing in the mid-to high 80’s and now you are struggling to touch 80mph. “What happened?  What is wrong with my arm?”


Dead Arm is truly one of baseball’s biggest mysteries and can affect both pitchers and position players. The symptoms can be associated with and without pain but one of the defining characteristics is the feeling that the shoulder “catching on something” or the throwing motion is not “smooth.”  Many players think their arm is injured and get an MRI only to find out that there is no structural damage.

So what is going on with these arms that have no obvious structural damage?


Classic “Dead Arm” can occur when the rotator cuff muscles are fatigued or deconditioned. Perhaps the preseason conditioning exercises that stopped once the team started practicing and playing games has exhausted its benefits.

There are three imperatives to cure “Dead Arm”...

1. stretching the posterior capsule
2. strengthening, and
3. rest

However, in the middle of the season rest isn’t very appealing.


The shoulder relies on a delicate balance between the static (ligament) and dynamic (muscle) stabilizers to control the position of the humeral head (ball) in the glenoid (socket).  When this combination of static and dynamic stabilizers balance is interrupted by the weakening or overuse of these muscles, the muscles are rendered ineffective in offering dynamic stability in the shoulder and this loss of stability is enough to allow the humeral head to migrate superiorly (move up in the socket), causing a catching or impingement of the rotator cuff tendons, and or superior labrum. The humeral head without effective dynamic stabilization can also move forward in the glenoid (microinstability), enough to cause anterior subluxation (riding of the ball onto the anterior labrum). The posterior capsule (ligaments in the back of the shoulder joint) can tighten making the subluxation a perpetual problem.

Stretching the posterior capsule is a must for good arm care in the baseball player. This is done as part of the everyday warm up. Taking the throwing arm across the chest and stretching it to the point where the bicep muscle is getting very close to the neck.


Crossover Symmetry will help counter the effects of Dead Arm by strengthening the rotator cuff and scapular muscles in order to regain the delicate balance between the dynamic and static stabilizers. Additionally, the CS Advanced Plyometric Workout strengthens the fast twitch muscle fibers, the same muscle fibers that are used in high speed throwing which will lead to increased velocity."

For more information on this article, or to contact CrossOver Symmetry physical therapists, email info@crossoversymmetry.com

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