Glenohumeral rotation and scapular position adaptations after a single high school female sports season

Abstract

Context: Anterior instability and impingement are common in overhead athletes and have been associated with decreases in internal rotation (IR) and increases in external rotation (ER) motion. However, the chronology and the effect of different female sports on these conditions have yet to be determined.

Objective: To measure glenohumeral IR and ER rotation, total range of motion, and scapular position in female overhead athletes over a single competitive season.

Design: Multiple group pretest-posttest study.

Setting: High school.

Patients or other participants: Thirty-six female overhead athletes (age = 15.29 +/- 1.18 years, height = 164.16 +/- 7.14 cm, mass = 58.24 +/- 9.54 kg) with no history of shoulder or elbow surgery participating in high school swimming, volleyball, or tennis.

Intervention(s): Participants were measured for all dependent variables at preseason and postseason.

Main outcome measure(s): Participants were measured for glenohumeral IR and ER with the scapula stabilized. Total glenohumeral range of motion was calculated as the sum of IR and ER. Scapular upward rotation was measured at 0 degrees , 60 degrees , 90 degrees , and 120 degrees of glenohumeral abduction in the scapular plane, and scapular protraction was measured at 0 degrees , 45 degrees (hands on hips), and 90 degrees of glenohumeral abduction.

Results: Internal rotation decreased from preseason to postseason (P = .012). Swimmers had less IR than both volleyball and tennis players (P = .001). External rotation also decreased in the swimmers (P = .001). Overall, preseason to postseason total motion decreased for athletes participating in swimming (P = .001) and tennis (P = .019). For all participants, preseason to postseason scapular protraction at 45 degrees glenohumeral abduction decreased (P = .007).

Conclusions: Female overhead athletes demonstrated decreases in IR after only one competitive season. Clinically, our results indicate that overhead athletes should be monitored for motion changes throughout their competitive seasons.

Keywords: posterior shoulder capsule; scapular dyskinesis.

Figure 1. Measurement of scapular upward rotation using a modified digital inclinometer.

Figure 2. Measurement of scapular protraction using a vernier caliper.

Figure 3. Overall preseason to postseason glenohumeral internal rotation means (degrees). ^a Indicates difference between preseason and postseason (P < .05).

Figure 4. Overall glenohumeral internal rotation means for volleyball, tennis, and swimming athletes. ^a Indicates swimming was different from volleyball and tennis (P < .05).

Figure 5. Dominant and nondominant glenohumeral range-of-motion means (degrees). ^a Indicates the difference between internal rotation in dominant and nondominant shoulders (P < .05). ^b Indicates the difference between external rotation in dominant and nondominant shoulders (P < .05).

Figure 6. Overall glenohumeral total motion means for swimming, volleyball, and tennis athletes. ^a Indicates swimming was different from volleyball and tennis (P < .05).

Figure 7. Possible progression of overuse glenohumeral joint injuries in the overhead athlete. Abbreviations: GIRD, glenohumeral internal rotation deficit; ER, external rotation.