Pitch volume and glenohumeral and hip motion and strength in youth baseball pitchers

Abstract

Context: Increased pitch volume and altered glenohumeral (GH) and hip range of motion (ROM) and strength contribute to injury risk in baseball pitchers. Although these factors affect one another, whether they are related is unknown. Objective: To examine relationships among cumulative and seasonal pitch volume, ROM, and strength of the GH and hip joints in youth baseball pitchers. Design: Cross-sectional study. Setting: Baseball practice facilities. Patients or Other Participants: A total of 28 healthy baseball pitchers (age = 13.9 ± 2.9 years). Main Outcome Measure(s): A demographic and pitching questionnaire was used to quantify pitch volume. Glenohumeral internal-rotation (IR) and external-rotation (ER) ROM and strength of the throwing arm; total arc of motion (IR + ER ROM); and bilateral hip IR, ER, and total arc of motion ROM and strength in IR, ER, and abduction were measured. A goniometer was used to assess ROM; a handheld dynamometer, to assess strength. Frequency analyses and bivariate correlations (age covariate) described data and identified relationships. Results: Correlations between years of competitive play and increased strength in lead-leg hip IR (r =0.52, P = .02) and abduction (r=0.48, P=.04) and stance-leg hip IR (r=0.45, P= .05) were fair to good. The number of months played in the last year had a fair correlation with decreased GH IR strength (r =-0.39, P = .04) and increased stance-leg hip IR strength (r = 0.44, P = .05). Limited pitch time had a fair correlation with increased GH ER ROM (r = 0.40, P = .04) and an excellent correlation with increased lead-leg hip IR ROM (r = 0.79, P < .001). Increased innings pitched per game had a fair to good correlation with decreased GH IR strength (r =-0.41, P = .04) and stance-leg hip ER ROM (r =-0.53, P = .03). More pitches per game had a fair to good correlation with increased GH ER ROM (r=0.44, P=.05) and decreased stance-leg hip ER ROM (r =-0.62, P = .008). Conclusions: The significant relationships identified in this study suggest the need to further examine youth and adolescent cumulative and seasonal pitch guidelines.