Androgen receptor gene microsatellite polymorphism is associated with muscle mass and strength in bodybuilders and power athlete status

Abstract

Background The androgen receptor (AR) gene contains a polymorphic trinucleotide (CAG) microsatellite repeat sequence (short or long alleles) that has been associated with fat-free mass in untrained men, which needs to be replicated in athletic cohorts. Aim The purpose of this study was to explore the AR (CAG)n polymorphism in trained individuals. Subjects and methods A total of 61 professional bodybuilders (40 males, 21 females), 73 elite male sprinters and weightlifters and 186 male controls were enrolled in this study. The influence of the AR (CAG)n polymorphism on muscle mass and strength was assessed in bodybuilders, while the frequencies of AR (CAG)n alleles were compared between power athletes and non-athletes. Results The polymorphism was associated with anthropometric and strength measurements in bodybuilders of both genders. Those with ≥21 CAG repeats (i.e. carriers of long alleles) exhibited greater (p < 0.05) body mass index, absolute muscle mass, arm/thigh circumference and upper/lower limb strength compared to those with <21 CAG repeats. Furthermore, carriers of ≥21 CAG repeats were more frequent among power athletes compared to controls (p = 0.0076). Conclusions Long alleles of the AR (CAG)n polymorphism were associated with greater muscle mass and strength in bodybuilders, and power athlete status.