title: Sex differences in dynamic closed kinetic chain upper quarter function in collegiate swimmers.
abstract: BACKGROUND
  Upper quarter injuries have a higher incidence in female swimmers; however, to date, there are few ways to assess the basic functional ability of this region. The upper quarter Y balance test (YBT-UQ) may assist in this process because it was developed to provide a fundamental assessment of dynamic upper quarter ability at the limit of stability.
  
  
  OBJECTIVE
  To examine how sex affects performance on the YBT-UQ in swimmers.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Forty-three male and 54 female National Collegiate Athletic Association Division I college swimmers were recruited preseason.
  
  
  METHODS
  We measured YBT-UQ performance for the left and right limbs in the medial, inferolateral, and superolateral directions. The maximum score for each direction was normalized to upper extremity length. The average of the greatest normalized reach scores in each reach direction was used to develop a composite score (average distance in 3 directions/limb length [LL] × 100). To examine reach symmetry between sexes, the difference in centimeters between the left and right sides was calculated for each reach direction prior to normalization. Statistical analysis was conducted using an independent-samples t test (P < .05).
  
  
  RESULTS
  Average scores in the medial (women: 92.5 ± 7.4%LL, men: 100.0 ± 8.7%LL; P < .01) and inferolateral (women: 85.6 ± 10.3%LL, men: 89.8 ± 10.8%LL; P = .05) directions and composite score (women: 83.4 ± 8.3%LL, men: 88.3 ± 8.9%LL; P < .01) were higher in men than in women. No differences were observed for reach symmetry in any direction.
  
  
  CONCLUSIONS
  Performance on several YBT-UQ indices was worse for female than male collegiate swimmers. These results may have implications for the use of preseason and return-to-sport testing in swimmers as a measurement of upper quarter function and symmetry.
authors.affiliation: Duke University, Durham, NC.
authors.forename: Robert
authors.initials: R
authors.lastname: Butler
authors.forename: Jennifer
authors.initials: J
authors.lastname: Arms
authors.forename: Michael
authors.initials: M
authors.lastname: Reiman
authors.forename: Phillip
authors.initials: P
authors.lastname: Plisky
authors.forename: Kyle
authors.initials: K
authors.lastname: Kiesel
authors.forename: Dean
authors.initials: D
authors.lastname: Taylor
authors.forename: Robin
authors.initials: R
authors.lastname: Queen
mesh_terms: D001265:Athletic Injuries / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D016059:Range of Motion, Articular / Q000502:physiology*; D012307:Risk Factors; D012737:Sex Factors; D012782:Shoulder / Q000503:physiopathology*; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000503:physiopathology*; D013550:Swimming / Q000293:injuries*; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Y-Balance test; core stability; injury risk; shoulder function