title: Asymmetric Hip Rotation in Professional Baseball Pitchers.
abstract: BACKGROUND
  There is a renewed interest in examining the association between hip range of motion and injury in athletes, and the data on baseball players are conflicting. Understanding whether asymmetrical hip rotation is a normal adaptation or a risk factor for injury will help therapists, trainers, and physicians develop rehabilitation programs to improve kinetic energy transfer and prevent injury. As our knowledge of hip pathology among baseball pitchers improves, establishing baselines for hip motion is critical in the further assessment of injury.
  
  
  OBJECTIVE
  Because of the repetitive nature of throwing sports and the adaptive changes documented in the shoulder, elite baseball pitchers would have characteristic patterns of hip internal and external rotations on their dominant throwing side (stance) and their nondominant side (stride) in extension.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  Computer software was used to measure passive internal and external rotations on digital photographs of 111 professional baseball pitchers.
  
  
  RESULTS
  In right-handed pitchers, there was significantly more internal rotation in the stance hip than the stride hip (32.2° ± 8.2° vs 30.8° ± 8.4°; P = .0349) and significantly more external rotation in the stride hip than the stance hip (36.3° ± 7.7° vs 30.8° ± 9.7°; P < .0001). While the mean difference in external rotation was 4.7°, 32% of the subjects had a >10° increase in external rotation on the stride hip relative to the stance hip. This population was statistically different from the remaining group for older age (P = .0053), lower body mass index (P = .0379), and more years in professional baseball (P = .0328). In the smaller number of left-handed pitchers, side-to-side differences in hip rotation were found but were not statistically significant.
  
  
  CONCLUSIONS
  Pitchers showed more internal rotation on their stance hip and more external rotation on their stride hip. Although the mean differences are small, there is a subset of pitchers with defined characteristics in whom larger differences exist.
authors.affiliation: Houston Methodist Hospital, Houston, Texas, USA.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: McCulloch
authors.affiliation: Houston Methodist Hospital, Houston, Texas, USA.
authors.forename: Jayesh K
authors.initials: JK
authors.lastname: Patel
authors.affiliation: Institute of Orthopedic Research and Education, Houston, Texas, USA. ; Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Prem N
authors.initials: PN
authors.lastname: Ramkumar
authors.affiliation: Institute of Orthopedic Research and Education, Houston, Texas, USA.
authors.forename: Philip C
authors.initials: PC
authors.lastname: Noble
authors.affiliation: Houston Methodist Hospital, Houston, Texas, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Lintner
keywords: baseball pitchers; hip rotation