Glenohumeral Range of Motion and Lower Extremity Flexibility in Collegiate-Level Baseball Players

Abstract

Background: The throwing motion results in unilateral increases in dominant arm external rotation (ER) range of motion (ROM). Trunk forward tilt at ball release is related to ball velocity. The relationship between lower quarter flexibility and dominant arm ROM is not known. Hypothesis: There is a relationship between lower extremity flexibility and dominant arm ER ROM and total rotation ROM. Study Design: Prospective cohort study. Methods: Forty-two collegiate baseball pitchers were studied. Demographics, dominant arm, and bilateral glenohumeral ER and internal rotation (IR) ROM were measured. Lower quarter flexibility was assessed via sit-and-reach test. Total rotation motion (TRM) was calculated as ER + IR = TRM. Paired t tests examined differences between the dominant and nondominant arms for ER, IR, and TRM; Pearson product-moment correlation coefficients, shoulder ROM and lower extremity flexibility variables (α = 0.05). Results: ER mean value was significantly greater, and IR mean value significantly less, in the dominant arm. TRM mean values were not significantly different bilaterally. Sit-and-reach results were strongly correlated with TRM and ER of the dominant arm. Conclusions: There was a significant shift in TRM toward ER in collegiate baseball players. Lower quarter flexibility was strongly correlated with dominant arm ER and total rotation ROM but not in the nondominant arm. Clinical Relevance: The sit-and-reach test may be useful to identify a pitcher’s potential to achieve an appropriate amount of trunk forward tilt. This may maximize the lag effect necessary to achieve maximum ER of the dominant arm and increased ball velocity.