title: ACTN3 genotypes of Rugby Union players: distribution, power output and body composition.
abstract: OBJECTIVE
  To identify the distribution and explore the relationship between ACTN3 genotypes and power and body composition phenotypes.
  
  
  METHODS
  Case control and association studies were employed using a homogeneous group of players (n = 102) and a control group (n = 110). Power-related phenotypes were measured using the counter movement jump (CMJ) and body composition phenotypes by dual-energy X-ray absorptiometry (DXA). Statistics used were Pearson's chi-square, ANCOVA, coefficients of correlation and independent t-tests. Genotyping was carried out using polymerase chain reaction followed by enzymatic Ddel digestion.
  
  
  RESULTS
  Genotype proportions of players were compared with controls (p = 0.07). No significant genotype differences occurred between forwards or backs (p = 0.822) or within-forwards (p = 0.882) or within-backs (p = 0.07). Relative force and velocity were significantly larger in backs, power significantly greater in forwards; in body composition, all phenotypes were significantly greater in forwards than backs. Correlations between phenotypes were greater for the RX genotype (p = 0.05-0.01).
  
  
  CONCLUSIONS
  Relationships between ACTN3 genotypes and power or body composition-related phenotypes were not significant. As fat increased, power-related phenotypes decreased. As body composition increased, power-related phenotypes increased.
authors: Cardiff Metropolitan University, Cyncoed, Cardiff, Wales, UK. wbell@uwic.ac.uk
authors: W
authors: W
authors: Bell
authors: J P
authors: JP
authors: Colley
authors: W D
authors: WD
authors: Evans
authors: S E
authors: SE
authors: Darlington
authors: S-M
authors: SM
authors: Cooper
mesh_terms: D000185:Actinin / Q000235:genetics*; D000293:Adolescent; D056352:Athletes; D001696:Biomechanical Phenomena / Q000235:genetics; D001823:Body Composition / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005538:Football; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D055815:Young Adult
chemical_list: C118456:ACTN3 protein, human; D000185:Actinin