title: Comparison of postural stability between injured and uninjured ballet dancers.
abstract: BACKGROUND
  Ballet movements require a limited base of support; thus, ballet dancers require a high level of postural control. However, postural stability in ballet dancers is still unclear and needs to be understood.
  
  
  OBJECTIVE
  To evaluate ballet dancers' postural stability in performing single-leg standing, the en pointe task, and the first and fifth positions and to determine differences in task performance among healthy nondancers, healthy dancers, and dancers with ankle sprains.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Injured dancers, uninjured dancers, and nondancers were recruited for this study (N = 33 age-matched participants; n= 11 per group). The tasks tested were single-leg standing with eyes open and closed, first position, fifth position, and en pointe. Center of pressure parameters were calculated from the ground-reaction force collected with 1 force plate. Analysis of variance was used to assess the differences of center of pressure parameters among 3 groups in single-leg standing; independent t test was used to examine the differences of center of pressure parameters between injured and uninjured dancers.
  
  
  RESULTS
  During single-leg standing, injured dancers had significantly greater maximum displacement in the medial-lateral direction and total trajectory of center of pressure, compared with the uninjured dancers and nondancers. During the first and fifth positions, the injured dancers demonstrated significantly greater standard deviation of center of pressure position in the medial-lateral and anterior-posterior directions, compared with the uninjured dancers. During en pointe, the injured dancers had significantly greater maximum displacement in the medial-lateral direction and the anterior-posterior direction, compared with the uninjured dancers.
  
  
  CONCLUSIONS
  The injured and uninjured dancers demonstrated differences in postural stability in the medial-lateral direction during single-leg standing and the ballet postures. Although the injured dancers received ballet training, their postural stability may still be inferior to that of the nondancers.
  
  
  CONCLUSIONS
  This study is a first step in understanding that injured ballet dancers do not have the same postural stability as uninjured dancers and that it is even inferior to that of nondancers, which is important to understand for further study on rehabilitation. The future development of effective balance training programs for ballet dancers with ankle injuries should emphasize improvements in medial-lateral directional balance.
authors.affiliation: Department of Physical Therapy, National Cheng Kung University, Tainan 70101, Taiwan. connie@mail.ncku.edu.tw
authors.forename: Cheng-Feng
authors.initials: CF
authors.lastname: Lin
authors.forename: I-Jung
authors.initials: IJ
authors.lastname: Lee
authors.forename: Jung-Hsien
authors.initials: JH
authors.lastname: Liao
authors.forename: Hong-Wen
authors.initials: HW
authors.lastname: Wu
authors.forename: Fong-Chin
authors.initials: FC
authors.lastname: Su
mesh_terms: D000293:Adolescent; D016512:Ankle Injuries / Q000503:physiopathology*; D003615:Dancing / Q000293:injuries* / Q000502:physiology*; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D004856:Postural Balance; D055815:Young Adult