Internal Impingement and GIRD in Throwers: The Sleeper Stretch Protocol
In short
A Glenohumeral Internal Rotation Deficit exceeding 20 degrees pinches the rotator cuff against the glenoid; targeted Sleeper stretches restore the total motion arc.
In this guide (4 sections)
The Biomechanics of Internal (Posterosuperior) Impingement
Unlike classical subacromial impingement (which pinches the rotator cuff under the anterior acromion in older non-athletes), internal impingement is a condition unique to overhead throwing and racquet athletes. It occurs during the extreme abduction and external rotation of the late cocking phase.
In this position, the articular (undersurface) side of the infraspinatus and supraspinatus tendons becomes mechanically pinched between the greater tuberosity of the humerus and the posterosuperior glenoid labrum. Chronic impingement produces articular-sided partial-thickness rotator cuff tears and posterior labral fraying.
Quantifying GIRD and the Total Arc of Motion
| Mobility Parameter | Normal Asymmetry in Throwers | Pathological GIRD Threshold | Clinical Risk Consequence | |
|---|---|---|---|---|
| Internal Rotation (IR) Loss | 5° to 15° loss compared to non-dominant arm | Greater than 20° loss of internal rotation | Doubles the risk of rotator cuff and labral tears | |
| External Rotation (ER) Gain | 5° to 15° gain on dominant throwing arm | Excessive ER gain (> 20°) with anterior laxity | Indicates stretched anterior capsule and micro-instability | |
| Total Arc of Motion (ER + IR) | Symmetrical (within 5° of non-dominant arm) | Total Arc deficit greater than 5° | Loss of total rotational arc is the premier predictor of throwing injury |
The Corrected Sleeper Stretch Protocol
- Side-Lying Scapular Lockout: Lie directly on the throwing shoulder with the torso rolled backward 20 to 30 degrees; this traps the lateral border of the scapula against the table, preventing scapular protraction from cheating the stretch.
- Passive Internal Rotation Overpressure: With the shoulder and elbow flexed to 90 degrees, use the opposite hand to gently push the wrist downward toward the table until a deep posterior shoulder stretch is felt; hold for 30 seconds for 3 repetitions.
- The Cross-Body Horizontal Adduction Alternative: If the Sleeper stretch triggers anterior subacromial pinching, substitute the cross-body stretch while the therapist manually stabilizes the lateral border of the scapula.
Frequently Asked Questions
What is GIRD in a baseball pitcher or cricket bowler?
GIRD stands for Glenohumeral Internal Rotation Deficit. It means your throwing shoulder has lost more than 20 degrees of inward rotation compared to your other arm, caused by a tight, scarred back shoulder capsule.
Why does my shoulder pinch in the back when I cock my arm to throw?
You have internal impingement. When you cock your arm back all the way, your rotator cuff tendon gets pinched between your arm bone and the back of your shoulder socket.
How does the Sleeper stretch help prevent throwing injuries?
The Sleeper stretch isolates and stretches the tight posterior shoulder capsule. Loosening this back capsule allows your arm bone to rotate properly, preventing it from riding upward and pinching your tendons.
Related condition guides
Related recovery guides & articles
BookPhysio.in Editorial Team
The BookPhysio.in editorial team writes and maintains this content, checking it against reliable clinical sources. Content follows our medical review policy: general information only, and no page claims a clinical review until a named registered physiotherapist has signed it off.
Read our medical review policy