title: The individual and combined influence of ACE and ACTN3 genotypes on muscle phenotypes before and after strength training.
abstract: Alternative measures of muscle size, strength, and power to those used in previous studies could help resolve the controversy surrounding associations between polymorphisms of the angiotensin-I converting enzyme (ACE) and α-actinin-3 (ACTN3) genes and skeletal muscle phenotypes, and the responses to resistance training (RT). To this end, we measured quadriceps femoris muscle volume (Vm), physiological cross-sectional area (PCSA), maximum isometric force (Ft), specific force (Ft per unit PCSA), maximum isoinertial strength (1-RM), and maximum power (Wmax ; n = 40) before and after 9-week knee extension RT in 51 previously untrained young men, who were genotyped for the ACE I/D and ACTN3 R577X polymorphisms. ACTN3 R-allele carriers had greater Vm, 1-RM, and Wmax than XX homozygotes at baseline (all P < 0.05), but responses to RT were independent of ACTN3 genotype (all P > 0.05). Muscle phenotypes were independent of ACE genotype before (all P > 0.05) and after RT (all P > 0.01). However, people with the "optimal" ACE+ACTN3 genotype combination had greater baseline 1-RM and Wmax compared to those with the "suboptimal" profile (both P < 0.0125). We show for the first time that the ACTN3 R577X polymorphism is associated with human Vm and (independently and in combination with the ACE I/D polymorphism) influences 1-RM and Wmax.
authors: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.|Centre for Genomic Research into Exercise, Performance and Health, Manchester Metropolitan University, Crewe, UK.
authors: R M
authors: RM
authors: Erskine
authors: Centre for Genomic Research into Exercise, Performance and Health, Manchester Metropolitan University, Crewe, UK.
authors: A G
authors: AG
authors: Williams
authors: Institute for Biomedical Research into Human Movement and Health, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK.
authors: D A
authors: DA
authors: Jones
authors: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.
authors: C E
authors: CE
authors: Stewart
authors: Institute for Biomedical Research into Human Movement and Health, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK.
authors: H
authors: H
authors: Degens
mesh_terms: D000185:Actinin / Q000235:genetics*; D000293:Adolescent; D005080:Exercise Test; D005787:Gene Frequency; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D054643:INDEL Mutation; D007537:Isometric Contraction; D008297:Male; D053580:Muscle Strength / Q000235:genetics*; D009929:Organ Size / Q000235:genetics; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D052097:Quadriceps Muscle / Q000033:anatomy & histology* / Q000502:physiology*; D055070:Resistance Training; D055815:Young Adult
chemical_list: C118456:ACTN3 protein, human; D000185:Actinin; D007703:Peptidyl-Dipeptidase A
keywords: angiotensin-I converting enzyme (ACE); gene polymorphisms; interindividual variability; resistance training; skeletal muscle; α-actinin-3 (ACTN3)