2011 Volume 35 Issue 3 Pages 935-938
The aim of this study was to investigate the relationship between ROM of shoulder and medial elbow laxity in high school baseball players.
One hundred and five high school baseball players aged 15-17 years old underwent medical examination after fall baseball season had ended. Passive ROM of external rotation (ER) and internal rotation (IR) of the shoulder was measured bilaterally. Ultrasonography of the medial aspects of both elbows was performed to assess medial elbow laxity. Using the ultrasonograms, the increase of medial elbow joint space on the throwing side (Increase-MEj) was calculated, compared to the non-throwing side. The ROM of ER was 128° on the throwing side and 115° on the non-throwing side. The ROM of IR was 45° on the throwing side and 65° on the non-throwing side. The mean increase-MEj was 1.0mm. 11 subjects had the increase-MEj of 2.5mm or more (laxity group), and 94 had the increase-MEj of < 2.5 mm (normal group). In the laxity group, the ROM of ER was 136° on the throwing side, and that in the normal group, the corresponding ROM was 128°. Compared with the normal group, the ROM of ER in the laxity group was significantly increased. There was no difference in the ROM of IR between the laxity group and the normal group.
The ROM of external rotation of the shoulder could be correlated with medial elbow laxity in high school baseball players.
