Shoulder motion and laxity in the professional baseball player.

We studied 148 professional baseball players with no history of shoulder problems to assess range of motion and laxity of their dominant and nondominant shoulders. There were 72 pitchers and 76 position players. Average external rotation with the arm in 90 degrees of abduction was statistically greater and average internal rotation was statistically less in the dominant shoulders than in the nondominant shoulders, both in pitchers and position players. There was no statistical difference in forward elevation of external rotation with the arm at the side of the body in either group. Both dominant and nondominant shoulders of pitchers had greater average range of motion in forward elevation and external rotation (both at the side and at 90 degrees of abduction) and less average internal rotation than those of position players. Regarding laxity testing, 61% of dominant shoulders in pitchers had a sulcus sign, as compared with 47% in position players. Also, this degree of inferior laxity was significantly greater in pitchers than in position players. Differences in range of motion and laxity exist in the throwing shoulder of athletes involved in overhead throwing motions and should be considered in rehabilitation protocols and surgical repair.