Thrower's Shoulder

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Original Editors

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Search Strategy

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Definition/Description

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Epidemiology /Etiology

While many sports involve overhead throwing, baseball pitchers compromise a plurality of those throws and over half of the throws made in a baseball game.

Characteristics/Clinical Presentation

• Thrower's Paradox - The balance between mobility and functional stability. -JM_Wilk Article

The ability to provide the best physical therapy for the throwing patient involves understanding the phases and biomechanics behind throwing. It is important to note that while these athletes are throwing with their arms, that they gain a large, important amount of momentum and force through the use of their legs and torso. This section will mostly pertain to the upper extremity's influence on throwing.

The picture below depicts an overhead view of the alignment of the body during the acceleration phase of throwing. Note the 15 degree angle of the foot away from the center of the mound. The stride ankle also typically lands approximately 10cm away from the same midline with a distance from the rubber averaging 87% of the pitcher's height. Fleisig emphasizes the importance of these values by describing the change in force exhibited on the shoulder when they deviate from the norm. During the cocking phase, Fleisig reports a 3.0N increase in anterior force at the shoulder for every extra cm. and a 2.1N increase in anterior force at the shoulder with every degree increase. Please note that decreasing the distance away from center or decreasing the angle did not result in increased anterior force on the shoulder. So, because of the increased anterior force on the shoulder, it can be assumed that over time the anterior ligamentous structures to the glenohumeral joint may be compromised. This finding is consistent with the anterior glenohumeral instability found in many throwing athletes and emphasizes the importance of proper mechanics throughout the entire kinematic chain.

File:Pitching angle foot and leg.png

Image:Pitching_angle_foot_and_leg.png

 

There is inconclusive evidence as to whether or not glenohumeral external rotation during the earlier phases of throwing (such as stride foot contact) has a positive or negative impact on throwing kinematics or injury occurrence. Some studies claim that increased external rotation increases the risk for injury while others refute the same statement. It is hypothesized that total amount of external rotation at the glenohumeral joint (PROM) may be predictive of increased throwing velocity and increased risk for injury at the glenoid labrum and/or rotator cuff, especially when the loss of internal rotation exceeds the gained external rotation. It is possible that the mechanism for labral tear is caused by the deceleration force imposed by the biceps tendon's attachment to the superior labrum.

Differential Diagnosis

• Rotator Cuff Tear
• Rotator Cuff Tendonosis/itis
• SLAP Lesions
• Subacromial Impingement
• Internal Impingement
• Primary Instability
• Bennet's Lesion
• Acute Traumatic Instability
• Improper Mechanics

Examination

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Medical Management (current best evidence)

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Physical Therapy Management (current best evidence) 

Pitchers have the option of throwing from "The Stretch" or "The Wind-up" positions. It is important for them to be comfortable with both deliveries and for both to be mechanically similar during the follow-through phase.

"The Stretch" vs "The Wind-up"

Wilk, Meister, and Andrews define 4 phases to the rehab of the throwing athlete: Acute, Intermediate, Advanced Strengthening, and Return-to-Throwing. They also discuss more specific rehab principles for common injuries to overhead throwing athletes. These rehab specifics will be illustrated in the following charts.

File:Shoulder acute phase rehab2.png

 

File:Shoulder intermediate phase rehab.png

 

File:Shoulder advanced strengthening rehab phase.png

File:Shoulder return to throwing phase.png

Return To Throwing Interval Program - Developed by Raymond "Smokey" Kubacak, PT

Throwers' Ten Exercise Program

Key Research

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Resources

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Clinical Bottom Line

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Recent Related Research (from Pubmed)

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References

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