We know athletes who throw overhead have more torn shoulder tendons than the average Joe. MRI results have shown this in many studies. But it may not be fair to compare athletes to non-athletes. The dominant arm of an athlete performs many overhead motions. Unathletic volunteers just don’t have the same stresses and loads.
Researchers at the North Carolina Sports Performance Center compared the dominant arm in athletes to the athlete’s other (nondominant) arm. MRI was used to show any injuries that were present but not causing symptoms. Five years later, the researchers contacted the athletes again to see if anything ever came of their asymptomatic injuries.
The MRI findings showed that 40 percent of the athletes had a torn rotator cuff in the dominant arm. The other arm was injury-free for all subjects. Another 25 percent had a different injury called Bennett’s lesion, which is a tear in the cartilage. Despite these injuries, no one had any loss of motion or strength. None of the other tests were positive for tendon or cartilage tears.
And five years later, no one had any symptoms or shoulder problems. This left the researchers wondering if the abnormal MRI signals are a sign of a developing problem or just a false positive test. (False positive means the test shows something’s wrong when there isn’t really anything there.)
The authors drew the following conclusions: