Glenohumeral joint rotation range of motion in competitive swimmers.
Riemann BL, Witt J, Davies GJ. J Sports Sci. 2011 Aug;29(11):1191-9. Epub 2011 Jul 22.
Side to side shoulder ROM changes in overhead athletes is nothing new. Previous studies have noted that with repetitive overhead sporting activities, most notably baseball, we can expect to see an increase in dominant arm external rotation and a concomitant decrease in internal rotation. While this occurs in athletes performing unilateral UE activities, what isn’t so clear is what type of shoulder ROM changes can be expected in individuals performing bilateral UE sporting activities. On the surface, it is tempting to believe that there will be equal ROM changes bilaterally. In this article Reimann et al. studied 144 competitive swimmers, aged between 12-61 years (broken down into age subcategories of youth, high school, college and master’s). Recruitment was based on the following criteria: >1 year experience, >3 practice sessions/week and no recent history of shoulder pain or injury. The motions that were examined included ER, isolated 90/90 IR (glenohumeral IR only), composite IR (90/90 IR + scapular protraction) and the total arc of motion (ER+ composite IR). The authors investigated 3 different hypotheses. First they stated that there would be no difference between men and women. They found that all age groups except youth men and master’s women had significant increases in dominant arm ER ROM. Of note, significant increases in non-dominant UE isolated IR, composite IR and total arc of motion were seen in the subjects regardless of age and gender. Secondly the authors believed that the dominant shoulder would have greater ROM in all directions than the non-dominant arm. Parts of the second hypothesis were supported, but a lack of significant dominant side ER ROM for youth men and master’s women swimmers prevented the authors from being able to fully prove their hypothesis. These same swimmers (youth men & master’s women) also had greater non-dominant isolated IR, composite IR and total arc of motion. Lastly, the authors believed that younger swimmers would have significantly more ROM than the older swimmers. This third hypothesis also was partially supported. The youth and high school swimmers exhibited significantly larger ROM values for composite IR when compared to college and master’s-aged swimmers. They also had significantly greater total arc of motion values when compared against all other groups.
The authors believe that several factors may be influencing the results. First, in regards to dominant side ER increases, they state that this might be due to limb bias during activity of daily living. While the athlete is performing a bilateral UE sporting task, the repetitive and cumulative effects of their actions out of the water could be playing a role in the data that they obtained. Second, the authors theorize that the IR increases seen in the swimmers’ non-dominant side could be related to the preferred side of breathing, which is often times their dominant arm side. They suggest that it may be plausible that more IR is needed on the non-dominant side in an effort to continue to propel the swimmers as their body rolls during breathing. Lastly, the authors believe that the greater ROM values seen in the younger subjects is potentially due to fewer years of repetitive training as well as inherent greater ROM values seen in a younger population. This study does a good job of clarifying what sports medicine professionals can reasonably expect to see when doing pre-participation screening for various healthy swimming populations. The next logical step would be to do a follow-up study examining ROM in an injured swimming population. What are your thoughts on this study? Are you surprised that there isn’t more ROM uniformity between both UE’s after participating in a task like swimming? What is your experience when examining a healthy swimmer? Are you looking critically at the athlete and taking into account age, gender and limb dominance when you examine them?
Written by: Mark Rice
Reviewed by: Stephen Thomas