title: Genetic associations of body composition, flexibility and injury risk with ACE, ACTN3 and COL5A1 polymorphisms in Korean ballerinas.
abstract: OBJECTIVE
  The purpose of this study was to exam the association of body composition, flexibility, and injury risk to genetic polymorphisms including ACE ID, ACTN3 RX, and COL5A1 polymorphisms in ballet dancers in Korea.
  
  
  METHODS
  For the purpose of this study, elite ballerinas (n = 97) and normal female adults (n = 203) aged 18 to 39 were recruited and these participants were tested for body weight, height, body fat, fat free mass, flexibility, injury risks on the joints and gene polymorphisms (ACE, ACTN3, COL5A1 polymorphism).
  
  
  RESULTS
  As results, the ACE DD genotype in ballerinas was associated with higher body fat and percentage of body fat than the ACE II and ID genotypes (p < 0.05). In the study on the ACTN3 polymorphism and ballerinas, the XX genotype in ballerinas had lower body weight and lower fat-free mass than the RR and RX genotype (p < 0.005). Also, the means of sit and reach test for flexibility was lower in the ACTN3 XX genotype of ballerinas than the RR and RX genotype of ballerinas (p < 0.05). Among the sports injuries, the ankle injury of the XX-genotyped ballerinas was in significantly more prevalence than the RR and XX-genotyped ballerinas (p < 0.05). According to the odd ratio analysis, XX-genotyped ballerinas have the injury risk on the ankle about 4.7 (95% CI: 1.6~13.4, p < 0.05) times more than the RR and RX-genotyped ballerinas. Meanwhile, the COL5A1 polymorphism in ballerinas has no association with any factors including flexibility and injury risks.
  
  
  CONCLUSIONS
  In conclusion, ACE polymorphism and ACTN3 polymorphism were associated with ballerinas' performance capacity; COL5A1 was not associated with any factors of performance of Ballerinas. The results suggested that the ACE DD genotype is associated with high body fat, the ACTN3 XX genotype is associated with low fat-free mass, low flexibility, and higher risk of ankle-joint injury.
authors.affiliation: School of Dance, Kyunghee University, Seoul, Korea.
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: School of Dance, Kyunghee University, Seoul, Korea.
authors.forename: Eun Sun
authors.initials: ES
authors.lastname: Jung
authors.affiliation: Department of Sports Medicine, Soonchunhyang University, Asan, Korea.
authors.forename: Chul-Hyun
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Judo, Yong In University, Yong In, Korea.
authors.forename: Hyeon
authors.initials: H
authors.lastname: Youn
authors.affiliation: School of Dance, Kyunghee University, Seoul, Korea.
authors.forename: Hwa Rye
authors.initials: HR
authors.lastname: Kim
keywords: ACE; ACTN3; COL5A1; ballet; body composition; flexibility; injury risk