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

Abstract

Objective: To investigate shoulder-rotator strength, internalrotation (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 ¼ 16.0 6 1.4 years, height ¼ 179.2 6 9.0 cm, mass ¼ 67.1 6 10.9 kg, body mass index ¼ 20.7 6 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 ¼ 4.92, P , .001), but IR ROM (t 38 ¼ À8.61, P , .001) and total ROM (t 38 ¼ À3.55, P ¼ .01) were less in the dominant shoulder, and 15 athletes had a glenohumeral IR deficit (IR ROM loss . 188). We observed greater concentric internal-rotator (t 38 ¼ 2.89, P ¼ .006) and eccentric external-rotator (t 38 ¼ 2.65, P ¼ .01) strength in the dominant than in the nondominant shoulder. The AHD was less in the dominant shoulder (t 38 ¼ À3.60, 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.Key Words: ultrasonography, sports, glenohumeral joint, muscle strength Key PointsAsymptomatic adolescent volleyball attackers demonstrated less internal-rotation range of motion (ROM), total ROM, and acromiohumeral distance and more external-rotation ROM in the dominant than in the nondominant shoulder, which might put them at risk for shoulder injuries. Routinely screening adolescent athletes and designing training programs to address hazardous adaptive changes could help prevent shoulder injuries.

Active Scapular Retraction and Acromiohumeral Distance at Various Degrees of Shoulder Abduction

“…This premise is supported by studies in which differences in AHD occurred when the scapula was passively positioned into retraction. Specifically, the AHD has been shown to increase at 608 of shoulder abduction (change in AHD range ¼ 0.6-1.2 mm) when the scapula was retracted passively by taping 18,19,26 and manual positioning. 17 Another potential explanation for the lack of a meaningful change in AHD with shoulder retraction in our study may be related to muscle recruitment.…”

“…3,15,16 Scapular-motion impairments thought to contribute to reduced AHD include decreased upward rotation and posterior tilting. 3,5 Several interventions directed at correcting altered scapular position, including manual (passive) techniques, 17 elastic taping or rigid taping of the scapula, 18,19 neuromuscular electrical stimulation of the scapular muscles, 20 and posterior-capsule stretching exercises, have been shown to increase AHD. 14 Scapular retraction has also been proposed as a means of improving the AHD during shoulder elevation.…”

“…It is thought to minimize the anterior tilt and internal rotation of the scapula, maintaining the AHD during shoulder elevation. 14,[17][18][19][20] To date, only Solem-Bertoft et al 21 have evaluated the influence of scapular retraction on AHD. They 21 reported that scapular retraction increased the AHD when compared with scapular protraction.…”

Specificity and spectrum of injuries among volleyball players

“… Anatomical and biomechanical conditions (abnormal mobility, asymmetry and muscle disproportion) and a history of pain for shoulder injuries,  Anatomical and biomechanical conditions for back injuries -the location of the body's center of gravity, body posture,  Common to shoulder and back injuries -utility technique, role on the court, level of game, exposure. Anthropometric measurements in the group of teenage volleyball attackers in the movement ranges of the shoulder joint showed specific adaptive changes in them [21]. These changes included a decreased range of internal rotation and acromiohumeral distance (AHD), and an increased range of external rotation.…”

Validity and reliability of shoulder strength assessment during scaption, internal rotation and external rotation using an anchored, non-modified sphygmomanometer

“…Muscle strength and length imbalances between these opposing muscle groups increase the risk for shoulder injuries. [8]. scaption is also a functional movement used during daily activities and requires deltoid, supraspinatus, and serratus anterior muscle activation [9].…”