title: The influence of winter vitamin D supplementation on muscle function and injury occurrence in elite ballet dancers: a controlled study.
abstract: OBJECTIVE
  Athletes who train indoors during the winter months exhibit low serum 25-hydroxyvitamin D [25(OH)D] concentrations due to a lack of sunlight exposure. This has been linked to impaired exercise performance. The purpose of this study was to assess the effects of oral vitamin D₃ supplementation on selected physical fitness and injury parameters in elite ballet dancers.
  
  
  METHODS
  Controlled prospective study.
  
  
  METHODS
  24 elite classical ballet dancers (intervention n=17; control n=7) participated in a controlled 4-month oral supplementation of vitamin D₃ (2000 IU per day). Isometric muscular strength and vertical jump height were measured pre and post intervention. Injury occurrence during the intervention period was also recorded by the in-house medical team. Repeated measures ANOVA and Mann-Whitney-U statistical tests were used and significance was set at p ≤ 0.05.
  
  
  RESULTS
  Significant increases were noted for the intervention group for isometric strength (18.7%, p<0.01) and vertical jump (7.1%, p<0.01). The intervention group also sustained significantly less injuries than the controls during the study period (p<0.01).
  
  
  CONCLUSIONS
  Oral supplementation of vitamin D₃ during the winter months has beneficial effects on muscular performance and injury occurrence in elite ballet dancers.
authors.affiliation: Research Centre for Sport Exercise and Performance, University of Wolverhampton, Walsall, UK; Jerwood Centre for the Prevention and Treatment of Dance Injuries, Birmingham, UK; National Institute of Dance Medicine and Science, UK. Electronic address: m.wyon@wlv.ac.uk.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Wyon
authors.affiliation: Research Centre for Sport Exercise and Performance, University of Wolverhampton, Walsall, UK; Institute of Human Performance and Rehabilitation, CERETETH, Trikala, Greece; Department of Sport and Exercise Sciences, University of Thessaly, Trikala, Greece.
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Koutedakis
authors.affiliation: National Institute of Dance Medicine and Science, UK; Department of Rheumatology and Sport and Exercise Medicine, Royal National Orthopaedic Hospital, Stanmore, UK.
authors.forename: Roger
authors.initials: R
authors.lastname: Wolman
authors.affiliation: Research Centre for Sport Exercise and Performance, University of Wolverhampton, Walsall, UK.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Nevill
authors.affiliation: Research Centre for Sport Exercise and Performance, University of Wolverhampton, Walsall, UK; Jerwood Centre for the Prevention and Treatment of Dance Injuries, Birmingham, UK; National Institute of Dance Medicine and Science, UK.
authors.forename: Nick
authors.initials: N
authors.lastname: Allen
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000517:prevention & control*; D002762:Cholecalciferol / Q000494:pharmacology / Q000627:therapeutic use*; D003615:Dancing; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000187:drug effects*; D012621:Seasons; D014815:Vitamins / Q000494:pharmacology / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D014815:Vitamins; D002762:Cholecalciferol
keywords: Ballet; Injury; Isometric strength; Vertical jump; Vitamin D