Total Shoulder Range of Motion in an Overhead Throwing Athlete

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          If you were to compare an overhead athlete’s total shoulder range of motion, to that of a regular person, you would see that they would not look very similar. In a regular person, if you were to measure their internal (IR) and external rotation (ER), you would see that they would be 70-90 degrees and 90 degrees each, respectively.² Conversely, if you were to measure an overhead athlete’s total range of motion, they would have more external rotation and a smaller amount of internal rotation in their dominant arm. In a study done by Freehill et. al, they measured the total rotational range of motion in MLB pitchers. It was found that their ER was 124.8 ± 19.5 degrees, and their IR was 70.9 ± 11.8 degrees.¹ Granted these are professional athletes at the highest level, however it illustrates the point that throwing athletes make up in ER what they lack in IR. It was concluded that this natural adaptation resulted from acute musculoskeletal adaptations¹ in overhead throwing athletes, to gain velocity throws.

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     The loss of internal rotation is known as GIRD, or glenohumeral internal rotation deficit. GIRD, which many believed could make an individual more susceptible to injury was something that would be stressed in rehabilitation settings. The worry lied within the athletes that were lacking internal rotation, because they would be more susceptible to developing injuries such as SLAP lesions (superior labral tear from anterior to posterior), and other shoulder related injuries. While it was true that GIRD did create the possibility of causing SLAP lesions, it was found that these lesions were often natural adaptations to allow overhead athletes such as a pitcher to throw harder by gaining more external rotation. Often the SLAPs are asymptomatic, and research done by Freehill et. al concluded that a cause-and-effect relationship between GIRD and significant shoulder injury had not been proven.¹ Research has found that if total rotational motion (ER + IR) is the same, as compared to the other arm, they are not predisposed to injury due to their lack of IR. Thus, in an athletic training setting, it is important to monitor total rotational range of motion in an overhead athlete’s throwing arm, and intervention may be necessary when it does not equate to the total motion of the other arm.

Works Cited:

Freehill, M. T., Ebel, B. G., Archer, K. R., Bancells, R. L., Wilckens, J. H., Mcfarland, E. G., & Cosgarea, A. J. (2010). Glenohumeral Range of Motion in Major League Pitchers: Changes Over the Playing Season. Sports Health: A Multidisciplinary Approach, 3(1), 97-104. doi:10.1177/1941738110374627

Moses, M. S. (2016, October 4). Shoulder Range of Motion. Retrieved October 06, 2016, from http://www.fpnotebook.com/ortho/exam/shldrrngofmtn.htm