Glenohumeral peak torques and strength ratios relationship with injury in adolescent female volleyball athletes

Abstract

Context: Research of adolescent volleyball athletes' isokinetic strength is nonexistent. Objective: 1"0 evaluate the relationship between shoulder injuries, anthropometric characteristics, and shoulder internal and external rotation strength. Design: Multivariate analysis of variance and covariance design with two conditions: (1) skill level and (2) previous shoulder injury. Setting: Human Performance and Athletic Training Labs at the University of Hawai'i, Manoa. Subjects: 38 adolescent club volleyball athletes, 10-15 years of age (mean 13.02 +1- 1.60). Main Outcome Measures: Concentric and eccentric peak torque of the shoulder internal and external rotators on a Biodex System 3 Dynamometer at 60°s-1 Results: Older and more skilled athletes had significantly higher peak torque measurements in concentric and eccentric internal/external rotation compared with the athletes of the younger and lesser skill levels. No differences existed between the healthy and injured subjects in terms of peak torque produced. Strength ratios were not different across skill levels, however injured subjects produced significantly lower eccentric internal rotation/concentric external rotation (p ~ 0.02) than healthy subjects. Conclusions: Differences in the internal and external shoulder rotator strength ratios appear to be related to injury prevalence more than absolute strength. Shoulder dysfunction related to strength ratio deficits may also exist in adolescent volleyball athletes.