Shoulder-Rotator Strength, Range of Motion, and Acromiohumeral Distance in Asymptomatic Adolescent Volleyball Attackers

Abstract

Context: Sport-specific adaptations at the glenohumeral joint could occur in adolescent athletes because they start participating in high-performance sports in early childhood. Objective: To investigate shoulder-rotator strength, internal-rotation (IR) and external-rotation (ER) range of motion (ROM), and acromiohumeral distance (AHD) in asymptomatic adolescent volleyball attackers to determine if they have risk factors for injury. Design: Cross-sectional study. Setting: University laboratory. Participants: Thirty-nine adolescent high school-aged volleyball attackers (22 boys, 17 girls; age = 16.0 +/- 1.4 years, height = 179.2 +/- 9.0 cm, mass = 67.1 +/- 10.9 kg, body mass index = 20.7 +/- 2.6 kg/m(2)). Main Outcome Measure(s): Shoulder IR and ER ROM, total-rotation ROM, glenohumeral IR deficit, AHD, and concentric and eccentric strength of the shoulder internal and external rotators were tested bilaterally. Results: External-rotation ROM was greater (t(38) = 4.92, P < .001), but IR ROM (t(38) = -8.61, P < .001) and total ROM (t(38) = -3.55, P = .01) were less in the dominant shoulder, and 15 athletes had a glenohumeral IR deficit (IR ROM loss >18 degrees). We observed greater concentric internal-rotator (t(38) = 2.89, P = .006) and eccentric external-rotator (t(38) = 2.65, P = .01) strength in the dominant than in the nondominant shoulder. The AHD was less in the dominant shoulder (t(38) = -3.60, P < .001). Conclusions: Adolescent volleyball attackers demonstrated decreased IR ROM, total ROM, and AHD and increased ER ROM in their dominant shoulder. Therefore, routine screening of adolescent athletes and designing training programs for hazardous adaptive changes could be important in preventing shoulder injuries.