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Updated: May 27, 2026

Clinical Anthropometrics and Body Composition from 3-Dimensional Optical Imaging
Published on: June 7, 2024
ACTN3 genotypes of Rugby Union players: distribution, power output and body composition
W Bell1, J P Colley, W D Evans
1Cardiff Metropolitan University, Cyncoed, Cardiff, Wales, UK. wbell@uwic.ac.uk
Background And Aim:
To identify the distribution and explore the relationship between ACTN3 genotypes and power and body composition phenotypes.
Subjects And 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.
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