title: Professional Pitchers With Glenohumeral Internal Rotation Deficit (GIRD) Display Greater Humeral Retrotorsion Than Pitchers Without GIRD.
abstract: BACKGROUND
  Dominant shoulder glenohumeral internal rotation deficit (GIRD) has been associated with pitching arm injuries. The relationship of humeral torsion on development of GIRD is not clear.
  
  
  OBJECTIVE
  Pitchers displaying GIRD will display greater humeral retrotorsion when compared with those without GIRD.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  Humeral torsion and shoulder range of motion (ROM) were measured in 222 professional pitchers before spring training from 2009 to 2012. Shoulder external rotation (ER) and internal rotation (IR) ROM were assessed in 90° of abduction with the scapula stabilized. Humeral torsion was measured via ultrasound using previously described and validated methods. Side-to-side differences in total arc of motion (ER + IR), ER, and IR ROM and humeral torsion were calculated as nondominant minus dominant arm measures for analysis. Pitchers were classified as having GIRD if their dominant arm displayed an IR deficit ≥15° concomitant with a total arc of motion deficit ≥10° compared with their nondominant arm. A mixed-model analysis of variance (side × GIRD) was used to compare dominant and nondominant humeral torsion between pitchers with GIRD (n = 60) and those without GIRD (n = 162). Independent t tests were used to compare the side-to-side difference in humeral torsion between pitchers with GIRD and those without GIRD (α = 0.05).
  
  
  RESULTS
  Pitchers with GIRD displayed significantly less humeral torsion (ie, greater retrotorsion) in their dominant arm as compared with those without GIRD (GIRD = 4.5° ± 11.8°, no GIRD = 10.4° ± 11.7°; P = .002). Pitchers with GIRD also displayed a greater side-to-side difference in humeral torsion (GIRD = 19.5° ± 11.9°, no GIRD = 12.3° ± 12.4°; P = .001). However, pitchers with GIRD did not display an increase in dominant ER ROM (dominant ER = 131.8° ± 14.3°, nondominant ER 126.6° ± 13.1°) when compared with those without GIRD (dominant ER = 132.0° ± 14.2°, nondominant ER 122.6° ± 13.1°; P = .03). Pitchers with GIRD displayed expected alterations in ROM (IR = 28.8° ± 9.6°, total arc = 160.6° ± 15.4°; P < .01 for both) when compared with those without GIRD (IR = 39.9° ± 9.9°, total arc = 171.2° ± 15.5°).
  
  
  CONCLUSIONS
  Pitchers with GIRD displayed greater side-to-side differences and dominant humeral retrotorsion as compared with those without GIRD. The greater humeral retrotorsion may place greater stress on the posterior shoulder resulting in ROM deficits. Pitchers with greater humeral retrotorsion appear to be more susceptible to developing ROM deficits associated with injury and may need increased monitoring and customized treatment programs to mitigate their increased injury risk.
authors: Steadman Hawkins Clinic Denver, Greenwood Village, Colorado, USA.
authors: Thomas J
authors: TJ
authors: Noonan
authors: Proaxis Therapy, Greenville, South Carolina, USA South Carolina Center for Rehabilitation and Reconstruction Science, Greenville, South Carolina, USA.
authors: Ellen
authors: E
authors: Shanley
authors: Memorial Hermann Ironman Sports Medicine Institute, Houston, Texas, USA.
authors: Lane B
authors: LB
authors: Bailey
authors: Steadman Hawkins Clinic of the Carolinas, Greenville, South Carolina, USA.
authors: Douglas J
authors: DJ
authors: Wyland
authors: Steadman Hawkins Clinic of the Carolinas, Greenville, South Carolina, USA.
authors: Michael J
authors: MJ
authors: Kissenberth
authors: Steadman Hawkins Clinic of the Carolinas, Greenville, South Carolina, USA.
authors: Richard J
authors: RJ
authors: Hawkins
authors: Proaxis Therapy, Greenville, South Carolina, USA South Carolina Center for Rehabilitation and Reconstruction Science, Greenville, South Carolina, USA chuck.thigpen@proaxistherapy.com.
authors: Charles A
authors: CA
authors: Thigpen
mesh_terms: D001484:Baseball / Q000293:injuries*; D003430:Cross-Sectional Studies; D006801:Humans; D006811:Humerus / Q000502:physiology; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology; D012399:Rotation; D012540:Scapula / Q000502:physiology; D012621:Seasons; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000503:physiopathology; D014102:Torsion Abnormality / Q000503:physiopathology*; D055815:Young Adult
keywords: baseball; glenohumeral internal rotation deficit (GIRD); range of motion (ROM)