A weak rotator cuff and overactive upper traps may be a major contributor to shoulder injury.
A new study examined 91 competitive tennis players to determine if there were any notable differences between those athletes who had a history of shoulder injury compared to those who had no shoulder problems. In the athletes who had shoulder injuries, the external rotators were weaker and the upper traps were stronger. Surprisingly, the athletes with a history of shoulder injury also had stronger serratus anterior muscles.
Conclusions
Many coaches and therapists have believed that strengthening the rotator cuff and preventing the upper trapezius from overcompensating for other muscles are important keys to injury prevention. This study lends support to these theories.
Interestingly, this study also found that the serratus anterior was overactive in the injured athletes, which is unusual because many experts have also stressed the importance of serratus strengthening exercises for prevention of shoulder injuries. Much value could be obtained from further research regarding which contexts the serratus becomes overactive vs underactive and what muscles it is compensating for when it becomes overactive.
Additionally, it is possible that the changes in the activity of these muscles could be a result of the shoulder injuries, rather than the cause of the injuries. Future research should include prospective data to determine whether these imbalances actually precede the onset of pain or injury.
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