Context: Conditions such as labral and rotator cuff injuries have been linked with decreases in glenohumeral internal-rotation and increases in external-rotation motion. Also, decreased glenohumeral internal rotation is strongly associated with scapular dyskinesis.
Objective: To compare healthy collegiate and high school baseball players' glenohumeral joint range of motion and scapular position.
Design: Cross-sectional study.
Setting: Institutional research laboratory.
Patients or other participants: Thirty-one male National Collegiate Athletic Association Division I collegiate (age = 20.23 +/- 1.17 years, height = 186.24 +/- 5.73 cm, mass = 92.01 +/- 7.68 kg) and 21 male high school baseball players (age = 16.57 +/- 0.76 years, height = 180.58 +/- 6.01 cm, mass = 79.09 +/- 11.51 kg).
Main outcome measure(s): Glenohumeral internal and external rotation and scapular upward rotation were measured with a digital inclinometer. Scapular protraction was measured with a vernier caliper. All variables except scapular upward rotation were calculated as the difference between the dominant and nondominant sides.
Results: Collegiate baseball players had more glenohumeral internal-rotation deficit (4.80 degrees, P = .028) and total motion deficit (5.73 degrees, P = .009) and less glenohumeral external-rotation gain (3.00 degrees, P = .028) than high school players. Collegiate baseball players had less scapular upward rotation than high school players at the 90 degrees (4.12 degrees, P = .015, versus 3.00 degrees, P = .025) and 120 degrees (4.00 degrees, P = .007, versus 3.40 degrees, P = .005) positions. The scapular protraction difference was greater in collegiate baseball players than in high school players in the hands-on-hips and 90 degrees positions (0.77 cm, P = .021, and 1.4 cm, P = .001).
Conclusions: When comparing high school with collegiate baseball players, these data suggest that glenohumeral internal-rotation deficit and scapular position change as the level of competition increases.