Shoulder Motion and Laxity in the Professional Baseball Player

Abstract

We studied 148 professional baseball players with no history of shoulder problems to assess range of motion and laxity of their dominant and nondominant shoul ders. There were 72 pitchers and 76 position players. Average external rotation with the arm in 90° of abduc tion was statistically greater and average internal rota tion was statistically less in the dominant shoulders than in the nondominant shoulders, both in pitchers and position players. There was no statistical differ ence in forward elevation or external rotation with the arm at the side of the body in either group. Both dom inant and nondominant shoulders of pitchers had greater average range of motion in forward elevation and external rotation (both at the side and at 90° 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 de gree of inferior laxity was significantly greater in pitch ers 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.