•  
  •  
 

COMPARISON OF PEAK SHOULDER DISTRACTION FORCES BETWEEN PAIN AND PAIN-FREE YOUTH BASEBALL PITCHERS

Abstract

Adam R. Nebel1, Anthony Fava1, Billy Lozowski1, Yuki Yanagita1, Thomas van Hogerwou2, Gretchen D. Oliver, FACSM1. 1Auburn University, Auburn, AL. 2Technical University of Delft, Delft.

Background: Increased shoulder distraction force during a baseball pitch may make a pitcher susceptible to rotator cuff or glenohumeral labrum injuries. A precursor to a pitching injury may be pain experienced at the throwing arm. Purpose: To compare peak shoulder distraction (PSD) forces in youth baseball pitchers with and without upper extremity pain when throwing a fastball. A secondary purpose was to determine if differences exist in the range of PSD forces between pain and pain-free groups. Methods: Thirty-six baseball pitchers were separated into pain-free (13.2 ± 1.7 yrs.; 164.4 ± 13.8 cm; 56.7 ± 15.2 kg; n = 17) and pain (13.3 ± 1.8 yrs.; 164.9 ± 12.5 cm; 56.7 ± 14.0 kg; n = 19) groups. Pitchers in the pain group had identified in a health history questionnaire that they experience pain in their upper extremity related to throwing a baseball. Pitching mechanics for a minimum of two fastballs per pitcher were recorded with an electromagnetic tracking system and motion capture software sampling at 240Hz. PSD force was normalized to the pitcher’s body weight (%BW), with intra-pitcher mean PSD (mPSD) calculated using each pitcher’s average PSD of the selected trials. Trials with the highest recorded PSD were used as max effort PSD (PSDmax). Intra-pitcher PSD range (rPSD) was calculated by finding the difference in the PSD force between the trial with the highest and lowest observed force. Statistical significance was set a priori to p < .05. Results: Mean PSD force was 114.96 ± 35.40%BW for the pain group and 96.62 ± 30.36%BW for the pain-free group. A one-tailed Mann-Whitney U-test revealed that pitchers in the pain group exhibited significantly higher PSDmax forces than those in the pain-free group (p = .04363, U = 107, z = 1.71). The mPSD forces (p = .08226, U = 117, z = 1.39425) and rPSD forces (p = .0537, U =103, z =1.606) were not significantly different between groups. Conclusion: The PSDmax force, when normalized to a pitcher’s body weight, was higher in the group experiencing pain while throwing fastballs than the group who reported they were pain-free while throwing. Further studies are needed to identify what other kinetics and kinematics may differ between pain and pain-free pitchers.

This document is currently not available here.

Share

COinS