Background: Research suggests that limitations in the hip motion of baseball players may lead to altered motion at the glenohumeral joint to maintain throwing velocity, thereby predisposing the upper extremity to injury.
Purpose: To measure and evaluate the correlation between hip and shoulder rotational range of motion (ROM) in healthy professional baseball players.
Study design: Descriptive laboratory study.
Methods: Ninety-nine professional baseball players (50 pitchers and 49 position players; mean age ± standard deviation [SD], 22 ± 2.8 years; mean height ± SD, 187 ± 5.4 cm; mean weight ± SD, 81.6 ± 7.7 kg) with no history of hip or shoulder injury were tested. Dominant and nondominant hip and glenohumeral joints were measured for the following passive ROM variables: (1) hip internal rotation (IR), (2) hip external rotation (ER), (3) total hip rotational ROM (IR + ER), (4) isolated glenohumeral IR, (5) isolated glenohumeral ER, and (6) total glenohumeral rotational ROM (IR + ER).
Results: Statistically, hip ER and total hip rotational ROM were greater in position players than in pitchers and less in the lead leg compared with the stance leg hip with groups combined; however, differences are not clinically meaningful. Pitchers had more glenohumeral rotational ROM than did position players. For all players, glenohumeral motion had less IR and greater ER in the throwing arm than the nonthrowing arm, but total glenohumeral rotational ROM was equivalent between sides. The correlations between hip and glenohumeral ROM were little, if any, and ranged from r = -0.19 to 0.11 (P = .006-.94) for all players and r = -0.29 to 0.23 (P = .04-.97) for pitchers only.
Conclusion: These data suggest no clinically meaningful differences in hip ROM between pitchers and position players and between lead leg and stance legs of all players. There is little or no relationship between hip and glenohumeral ROM in healthy professional baseball players.
Clinical relevance: The study findings add to the growing body of evidence that suggests an absence of chronic hip ROM adaptations. It is therefore suggested that in the hip, unlike the glenohumeral joint, symmetry in ROM between player positions and dominant and nondominant sides should be expected in healthy professional baseball pitchers and position players.
Keywords: athlete; external rotation; internal rotation; lower extremity; shoulder.