Glenohumeral (GH) internal-rotation deficit (GIRD) and lower eccentric external-rotator (ER) to concentric internal-rotator (IR) strength (ER:IR) ratio have been documented as risk factors for shoulder injuries, but there is no information on whether GIRD has an adverse effect on ER:IR ratio in adolescent overhead athletes.
The aim of this study was to investigate the effects of GIRD on functional ER:IR ratio of the adolescent overhead athletes.
University research laboratory.
52 adolescent overhead athletes.
Main Outcome Measures:
To determine GIRD, the range of GH IR and ER motion was measured with a digital inclinometer. An isokinetic dynamometer was used to assess eccentric and concentric IR and ER muscle strength of the dominant and nondominant shoulders. One-way ANCOVA where sport type was set as a covariate was used to analyze the difference between athletes with and without GIRD.
After standardized examinations of all shoulders, the athletes were divided into 2 groups, shoulders with (n = 27) and without GIRD (n = 25). There was a significant difference between groups in functional ER:IR ratio (P < .001). Athletes with GIRD had lower ER:IR ratio (0.56) than athletes without GIRD (0.83).
As GIRD has an adverse effect on functional ratio of the shoulder-rotator muscles, interventions for adolescent overhead athletes should include improving GH-rotation range of motion.
Guney, Harput, and Baltaci are with the Dept of Physiotherapy and Rehabilitation, Hacettepe University, Ankara, Turkey. Colakoglu is with the School of Physical Education and Sport, Gazi University, Ankara, Turkey.