title: Exploring Active and Passive Contributors to Turnout in Dancers and Non-Dancers.
abstract: Lower-extremity external rotation, or turnout, is a fundamental skill in dance. Active standing turnout has previously been measured using low-friction turnout disks. Turnout is influenced by passive range of motion (ROM) and strength, with passive ROM a function of bony morphology and ligamentous/capsular restraints.
  
  
  
  Our study explored the relationship between standing active turnout and femoral bony morphology, hip passive ROM, and strength among dancers and non-dancers.
  
  
  
  Cross-sectional cohort study. Twenty-three female dancers and 13 female non-dancers aged 18 to 30 yrs were recruited. Standing active turnout on reduced-friction disks, ultrasound images of femoral version, supine passive turnout, and hip abductor and external rotator strength were collected.
  
  
  
  Dancers demonstrated greater standing turnout (107° ± 18°) than non-dancers (92° ± 28°), but the difference was not statistically significant (p=0.054). A significant difference was found for femoral version (p<0.001), 4.7° ( ± 2.8°) for dancers vs 12.1° ( ± 4.6°) for non-dancers. Dancers demonstrated greater supine turnout, 102.7°±18.8°, compared to non-dancers, 84.3° ± 30.4° (p=0.031). Dancers were able to achieve greater peak force in turnout compared to non-dancers: 2.44 ± 0.44 N/kg and 1.72 ± 0.59 N/kg, respectively (p<0.0001). Supine total turnout was the best predictor of active turnout, contributing 48% of the variance (r=0.696, p<0.001).
  
  
  
  Our findings suggest supine turnout is the largest predictor for standing turnout. Investigating dancers and non-dancers independently, our finding were similar to previous studies suggesting the femoro-acetabular complex may be influenced by dance training, contributing to differences in bony morphology between dancers and non-dancers. Although strength did not significantly contribute to active standing turnout, dancers demonstrated greater peak force compared to non-dancers.
authors.affiliation: Musculoskeletal Biomechanics Research Laboratory, Division of Biokinesiology and Physical Therapy, University of Southern California, 1540 East Alcazar Street, CHP-155, Los Angeles, CA 90033, USA Tel 323-442-2911, fax 323-442-1515. kulig@usc.edu.
authors.forename: Kristen
authors.initials: K
authors.lastname: Sutton-Traina
authors.forename: Jo A
authors.initials: JA
authors.lastname: Smith
authors.forename: Danielle N
authors.initials: DN
authors.lastname: Jarvis
authors.forename: Szu-Ping
authors.initials: SP
authors.lastname: Lee
authors.forename: Kornelia
authors.initials: K
authors.lastname: Kulig
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology* / Q000648:ultrastructure; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003615:Dancing / Q000502:physiology*; D005260:Female; D006621:Hip Joint / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012399:Rotation; D055815:Young Adult