title: Glenohumeral and Hip Range-of-Motion and Strength Measures in Youth Baseball Athletes.
abstract: BACKGROUND
  The repetitive demands of throwing affect glenohumeral (GH) range of motion (ROM) and strength. Less is known about hip alterations in skeletally immature athletes.
  
  
  OBJECTIVE
  To compare GH and hip ROM and strength between age, position, and side of youth baseball athletes.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Multicenter testing.
  
  
  METHODS
  Seventy-two healthy baseball athletes. Participants' self-reported characteristics were age group (7-11 years [n = 28] or 12-18 years [n = 44]), position (pitcher [n = 22], position player [n = 47], unreported [n = 3]), and side (throwing or nonthrowing arm, lead or stance leg).
  
  
  METHODS
  Bilateral GH and hip internal- and external-rotation ROM were measured passively and summed for total arc of motion (TAM). Glenohumeral and hip rotation and gluteus medius strength were measured. Analyses included linear mixed models.
  
  
  RESULTS
  Glenohumeral internal rotation was less in throwing than in nonthrowing arms (P < .05) except in younger pitchers (P = .86). Compared with older athletes, younger athletes had more GH external rotation (103.3° ± 7.7° versus 97.5° ± 9.4°; P = .002), TAM (156.4° ± 8.7° versus 147.9° ± 10.9°; P = .04), and external rotation in throwing compared with nonthrowing arms (101.9° ± 1.2° versus 97.9° ± 1.1°; P < .001). Glenohumeral TAM was less in throwing than in nonthrowing arms (150.5° ± 2.1° versus 154.9° ± 1.3°; P = .01). Younger athletes had more hip internal rotation (38.9° ± 6.8° versus 31.2° ± 7.5°; P < .001) and TAM (68.4° ± 10.0° versus 60.7° ± 9.8°; P = .001) than older athletes. Lead-leg hip internal-rotation ROM was greater than in the stance leg (34.8° ± 8.9° versus 32.8° ± 7.7°; P = .01). Overall, older players were stronger than younger players (P < .05), and the throwing arm was stronger in internal rotation than the nonthrowing arm (10.12 ± 3.72 lb [4.59 ± 1.69 kg] versus 9.43 ± 3.18 lb [4.28 ± 1.44 kg]; P = .047).
  
  
  CONCLUSIONS
  Youth baseball athletes had typical GH ROM adaptations of less internal rotation and more external rotation in the throwing versus the nonthrowing arm. Greater ROM in younger athletes may be explained by prepubertal characteristics. We obtained hip-strength values in youth baseball athletes, and as expected, older athletes were stronger.
authors.affiliation: University of Kentucky, Lexington.
authors.forename: Kelsey J
authors.initials: KJ
authors.lastname: Picha
authors.affiliation: A.T. Still University, Mesa, AZ.
authors.forename: Josie L
authors.initials: JL
authors.lastname: Harding
authors.affiliation: A.T. Still University, Mesa, AZ.
authors.forename: Kellie C Huxel
authors.initials: KC
authors.lastname: Bliven
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D056352:Athletes; D001484:Baseball / Q000502:physiology*; D002648:Child; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D012399:Rotation; D012785:Shoulder Joint / Q000502:physiology*
keywords: adolescents; kinetic chain; shoulder; throwing athletes