Arm injuries are commonplace among Major League Baseball pitchers, and such impairments may have cost a few notable pitchers, such as Randy Johnson and Brandon Webb, a chance to play in the 76th All-Star Game tonight.

A pitcher’s shoulder joint can rotate as quickly as 7,000 degrees per second—nearly 20 complete revolutions in one second if the shoulder could rotate completely freely—during a pitch, making it one of the fastest movements possible by the body, and this repetitive motion of the arm contributes to the fatigue-related injuries. Ian Byram and his colleagues at Vanderbilt Medical Center are hoping to reduce the damage by identifying pitchers at risk for injury during the preseason, allowing teams to design unique strength training routines for susceptible athletes.
The group studied 144 major and minor league pitchers from the Colorado Rockies organization. Over a five-year period they took preseason strength measurements of the four muscles that make up the rotator cuff, which holds the shoulder joint intact. They found that weakness in the muscles for rotation away from the center of the body or for lateral movement increased a pitcher’s risk of sustaining an injury.

The results, presented at the American Orthopaedic Society of Sports Medicine conference last week, are the first data directly correlating preseason strength of the specific rotator cuff muscles with injury.  Byram also showed the data to the Colorado Rockies trainer last weekend and says the team is excited that the finding may be another useful tool to study players’ injuries.  

Image of Randy Johnson pitching by SD Dirk via flickr