Baseball Pitcher Shoulder Internal and External Rotational Range of Motion as an Injury Risk Indicator

Abstract

Prior research has demonstrated that pitchers with a deficit greater than five degrees in total rotation passive range of motion (TRM) in the dominant shoulder had a 2.6 times higher risk of injury to their elbow. PURPOSE: To evaluate the clinical utility of total range of motion (TRM), global internal rotation deficits (GIRD), and differences between rotational active and passive range of motion (A/PROM) as injury predictors among intercollegiate pitchers. METHODS: Fifteen division I baseball pitchers (age 19.4 ± 1.06 years; BMI 26.71 ± 1.92kg/m2) were tested during a competitive season. Range of motion measurements included active and passive external and internal rotation at 90° abduction in the scapular plane. TRM, GIRD, and A/PROM were compared between injured and uninjured players. RESULTS: Overall upper and lower body injury rate was 46.6% (seven out of 15). Elbow injury rate was 13.3% (two out of 15). Average difference in GIRD was 12.2 ± 13.92, in TRM was 23.07 ± 13.92, and in A/PROM was 37.13± 15.40. There were no statistically significant differences in TRM, GIRD, or A/PROM between the injured and non-injured groups. Pearson Chi-square analysis revealed no association between injury frequency with GIRD measurements >20 degrees for injured and uninjured. All participants of this study had TRM measurements > 5 degrees and A/PROM difference of >10 degrees. A/PROM difference of >40 degrees was analyzed between injured and uninjured with no significant difference. CONCLUSIONS: All pitchers in this study were at risk for elbow injury; two sustained injuries. Although not statistically significant, probably due to sample size, this is a much higher injury rate (13.3%) than previous research predicts (2.6%). The authors hypothesize it may be more appropriate to evaluate the difference of A/PROM to identify a motor control impairment as a cause of injury. Future studies should investigate the effects of upper extremity motor control on injury frequency among pitchers.