Exploration of myostatin polymorphisms and the angiotensin-converting enzyme insertion/deletion genotype in responses of human muscle to strength training

Abstract

This study explores the associations between polymorphisms in two candidate genes-myostatin gene (MSTN or GDF8) and angiotensin-converting enzyme (ACE) gene-with interindividual differences in human muscle mass and strength responses to strength training. The MSTN AluI A55T (exon 1), BanII K153R, TaqI E164 K and BstNI P198A (all in exon 2) markers and the ACE insertion (I)/deletion (D) polymorphism were typed in 57 males [22.4 (3.7) years] who participated in a 10-week, high-resistance training program for the elbow flexors. Maximal strength, and maximal isometric and concentric elbow flexor torques were measured at baseline and after training. Information on muscle cross-sectional area of the upper arm was obtained by computer tomography scans. Only one individual was heterozygous for the MSTN BanII K153R variant. No allelic variant was detected at the other MSTN sites in this population. For the ACE I/D polymorphism, no evidence was found for an association of the D or I allele with baseline strength, isometric and concentric torque or arm muscle cross-sectional area [analysis of covariance (ANCOVA) 0.25< P<0.97]. Responses to the strength-training program were not associated with the ACE I/D genotype (ANCOVA 0.057< P<0.70). Borderline significance was found for larger strength gains in dynamic flexion torques for I/I genotypes. This study therefore does not support the hypothesis that an increased muscle fiber hypertrophic effect of strength training is present in D-allele carriers.

ACE Genotype and the Muscle Hypertrophic and Strength Responses to Strength Training

“…More recently, Giaccaglia et al (9) have reported similar results in a population of obese older adults, such that 18 months of walking and light weight training resulted in greater gains in knee extensor strength in DD homozygotes compared with II homozygotes (9). In contrast, Pescatello et al (19) report greater increases in maximal voluntary contraction with training in carriers of the I allele than in DD homozygotes, and Thomis and colleagues (29) show no association with muscle adaptation to ST. Thus, previous studies present conflicting results regarding the potential role for ACE genotype with muscle strength phenotypes.…”

“…(19) and Thomis et al (29) fail to support the relationship between the D allele and muscle strength adaptation to ST. The few studies that have investigated the association between ACE genotype and muscle size responses to ST have observed no association in muscles of the upper arm (19,29), but no studies have examined the association in the weight-bearing lower limbs.…”

Genetic aspects of skeletal muscle strength and mass with relevance to sarcopenia

“…64,67,68,70 Most have reported no association with muscle mass and it appears unlikely that ACE genotype contributes significantly to muscle mass phenotypes.…”

Association of Genetic Factors With Selected Measures of Physical Performance

“…35 Several, more recent studies, which included populations with limited ethnic and geographic diversity, also do not support the previously reported associations of the ACE polymorphism with increased endurance or strength. Thomis and colleagues 36 recruited both members of 16 pairs of dizygotic twins and 1 individual who was a monozygotic twin to participate in a 10-week training session of bicep curls. Training sessions included 5 sets of bicep curls performed 3 times per week.…”

“…Each week the load was adjusted to a percentage of each subject's maximum for 1 repetition. On the basis of previous studies, Thomis and colleagues 36 hypothesized that the D allele of the ACE gene would correlate with greater strength gains; however, they demonstrated no evidence of an association of the ACE I/D polymorphism with gains in elbow flexor muscle cross-sectional area, maximum strength, or isometric and concentric strength after the high-resistance strength training program.…”