The influence of winter vitamin D supplementation on muscle function and injury occurrence in elite ballet dancers: A controlled study.

Abstract

OBJECTIVES: 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. DESIGN: 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 (2000IU 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.