Endurance-oriented athletes have a high proportion of slow-twitch muscle fibers (MF), whereas muscles of sprinters and strength athletes predominantly consist of fast-twitch MF. The heritability of the MF composition was estimated at 45%. PURPOSE: To perform a genome-wide association study for MF composition and to validate the results in additional studies using sport-related phenotypes. METHODS: MF composition of M. vastus lateralis in 168 physically active healthy Russian subjects (55 females, 113 males) was evaluated with immunohistochemistry. The case-control study involved 241 elite Russian athletes (89 sprinters, 49 strength athletes vs 103 endurance athletes). Twenty male wrestlers participated in the Wingate anaerobic test. Micro-array analysis (for detection of 700 K - 1.1 M single nucleotide polymorphisms (SNPs)) or whole-genome sequencing (wrestlers only) was used for genotyping. RESULTS: We first identified 929 SNPs that were associated (P<0.05) with the proportion of fast-twitch MF both in males and females. Next, we found that of the 929 SNPs, 37 variants were associated with sprinter athlete status (i.e. alleles associated with increased proportion of fast-twitch MF were over-represented in sprinters compared to endurance athletes). Of those, sprint-related alleles of 4 SNPs (rs7669580, rs1247330, rs2048968, rs2369665) were also over-represented in strength athletes (vs endurance athletes). Only rs7669580 SNP located in the LDB2 gene (encodes cytoskeletal protein) was found to be associated with the relative peak power in wrestlers. CONCLUSION: We have identified the A allele of the LDB2 rs7669580 SNP that was associated with increased proportion of fast-twitch MF (P=0.00046), ability to become a sprinter (P=0.021) or a strength athlete (P=0.016) and increased peak power of wrestlers (P=0.0187). The study was supported by grant from the Russian Science Foundation (Grant 17-15-01436).
It is generally accepted that muscle fibre composition may influence physical performance. The α-actinin-3 (ACTN3) gene R577X polymorphism is suspected to be one of the contributing gene variations in the determination of muscle fibre type composition and athletic status. In the present study, we examined the dependence of average preferred racing distance (PRD) on muscle fibre type composition of the vastus lateralis muscle in 34 subelite Russian speed skaters (20 men and 14 women) who competed in races of different length (500-10,000 m). We also investigated the association between the ACTN3 polymorphism and muscle fibre characteristics in 94 subjects (60 physically active healthy men and 34 speed skaters), as well as the relationship between PRD and ACTN3 genotype in 115 subelite and elite speed skaters. In addition, ACTN3 genotype and allele frequencies of the 115 speed skaters were compared with 1301 control subjects. The ACTN3 XX genotype frequency was significantly lower in sprinters (n = 39) compared with control subjects (2.6 versus 14.5%; P = 0.034). We observed a positive relationship between PRD and the proportion of slow-twitch muscle fibres that was close to linear, but better fitted a logarithmic curve (r = 0.593, P < 0.0005). The ACTN3 R577X polymorphism was associated with muscle fibre composition (slow-twitch fibres: RR genotype, 51.7 (12.8)%; RX, 57.4 (13.2)%; XX 61.5 (16.3)%; = 0.215; P = 0.049) in the overall muscle biopsy group, and with PRD of all athletes ( = 0.24, P = 0.010), indicating thatACTN3 XX genotype carriers exhibit a higher proportion of slow-twitch fibres and prefer to skate long-distance races. However, the majority of the association between muscle fibre type and PRD was independent of ACTN3 genotype. In conclusion, the ACTN3 R577X polymorphism is associated with preferred racing distance in speed skaters and muscle fibre type composition. Thus, it is probably partly via associations with fibre type that the R577X polymorphism contributes to a small but perhaps important component of the ability to perform at a high level in speed skating.
Responses of m. vastus lateralis to 8-week resistive training of various types at leg press mashine were investigated in 30 male subjects. Training loads were 25, 65 and 85% of one repetition maximum for low (LI), medium (MI), and high intensity (HI) training groups respectively, while angular velocities of contraction differed considerably between groups. The total work done during training session was identical. The maximum strengths during isokinetic knee extension in LI and HI groups were increased at most angular velocities. In group MI increments were obtained only during concentric contractions. Significant improvement of fatigue resistance and maximum oxygen consumption (V(O2max)) was seen only in group MI and LI, respectively. The training-related increase of cross-sectional area in type II fibers in m. vastus lateralis was in the order of HI > MI > LI group, and that of type I fibers was opposite. The increased myonuclear number was found for HI group. The data suggest that fiber hypertrophy, fatigue resistance and V(O2max) changes were related to the type of training.
Guilherme, JPLF, Egorova, ES, Semenova, EA, Kostryukova, ES, Kulemin, NA, Borisov, OV, Khabibova, SA, Larin, AK, Ospanova, EA, Pavlenko, AV, Lyubaeva, EV, Popov, DV, Lysenko, EA, Vepkhvadze, TF, Lednev, EM, Govorun, VM, Generozov, EV, Ahmetov, II, and Lancha Junior, AH. The A-allele of the FTO gene rs9939609 polymorphism is associated with decreased proportion of slow oxidative muscle fibers and over-represented in heavier athletes. J Strength Cond Res 33(3): 691-700, 2019-The purpose of this study was to explore the frequency of the FTO T > A (rs9939609) polymorphism in elite athletes from 2 cohorts (Brazil and Russia), as well as to find a relationship between FTO genotypes and muscle fiber composition. A total of 677 athletes and 652 nonathletes were evaluated in the Brazilian cohort, whereas a total of 920 athletes and 754 nonathletes were evaluated in the Russian cohort. It was found a trend for a lower frequency of A/A genotype in long-distance athletes compared with nonathletes (odds ratio [OR]: 0.65; p = 0.054). By contrast, it was found an increased frequency of the A-allele in Russian power athletes. The presence of the T/A + A/A genotypes rather than T/T increased the OR of being a Russian power athlete compared with matched nonathletes (OR: 1.45; p = 0.002). Different from that observed in combat sports athletes of lighter weight categories, the A-allele was also over-represented in combat sports athletes of heavier weight categories. The presence of the T/A + A/A genotypes rather than T/T increased the OR of being a combat sports athlete of heavier weight categories compared with nonathletes (OR: 1.79; p = 0.018). Regarding the muscle fibers, we found that carriers of the A/A genotype had less slow-twitch muscle fibers than T-allele carriers (p = 0.029). In conclusion, the A/A genotype of the FTO T > A polymorphism is under-represented in athletes more reliant on a lean phenotype and associated with decreased proportion of slow-twitch muscle fibers, while is over-represented in strength and heavier athletes.
Abstract Grishina, EE, Zmijewski, P, Semenova, EA, Cięszczyk, P, Humińska-Lisowska, K, Michałowska-Sawczyn, M, Maculewicz, E, Crewther, B, Orysiak, J, Kostryukova, ES, Kulemin, NA, Borisov, OV, Khabibova, SA, Larin, AK, Pavlenko, AV, Lyubaeva, EV, Popov, DV, Lysenko, EA, Vepkhvadze, TF, Lednev, EM, Bondareva, EA, Erskine, RM, Generozov, EV, and Ahmetov, II. Three DNA polymorphisms previously identified as markers for handgrip strength are associated with strength in weightlifters and muscle fiber hypertrophy. J Strength Cond Res 33(10): 2602–2607, 2019—Muscle strength is a highly heritable trait. So far, 196 single nucleotide polymorphisms (SNPs) associated with handgrip strength have been identified in 3 genome-wide association studies. The aim of our study was to validate the association of 35 SNPs with strength of elite Russian weightlifters and replicate the study in Polish weightlifters. Genotyping was performed using micro-array analysis or real-time polymerase chain reaction. We found that the rs12055409 G-allele near the MLN gene ( p = 0.004), the rs4626333 G-allele near the ZNF608 gene ( p = 0.0338), and the rs2273555 A-allele in the GBF1 gene ( p = 0.0099) were associated with greater competition results (total lifts in snatch and clean and jerk adjusted for sex and weight) in 53 elite Russian weightlifters. In the replication study of 76 sub-elite Polish weightlifters, rs4626333 GG homozygotes demonstrated greater competition results ( p = 0.0155) and relative muscle mass ( p = 0.046), adjusted for sex, weight, and age, compared with carriers of the A-allele. In the following studies, we tested the hypotheses that these SNPs would be associated with skeletal muscle hypertrophy and handgrip strength. We found that the number of strength-associated alleles was positively associated with fast-twitch muscle fiber cross-sectional area in the independent cohort of 20 male power athletes ( p = 0.021) and with handgrip strength in 87 physically active individuals ( p = 0.015). In conclusion, by replicating previous findings in 4 independent studies, we demonstrate that the rs12055409 G-, rs4626333 G-, and rs2273555 A-alleles are associated with higher levels of strength, muscle mass, and muscle fiber size.
Muscle fibre type is a heritable trait and can partly predict athletic success. It has been proposed that polymorphisms of genes involved in the regulation of muscle fibre characteristics may predispose the muscle precursor cells of a given individual to be predominantly fast or slow. In the present study, we examined the association between 15 candidate gene polymorphisms and muscle fibre type composition of the vastus lateralis muscle in 55 physically active, healthy men. We found that rs11091046 C allele carriers of the angiotensin II type 2 receptor gene (AGTR2; involved in skeletal muscle development, metabolism and circulatory homeostasis) had a significantly higher percentage of slow-twitch fibres than A allele carriers [54.2 (11.1) versus 45.2 (10.2)%; P = 0.003]. These data indicate that 15.2% of the variation in muscle fibre composition of the vastus lateralis muscle can be explained by the AGTR2 genotype. Next, we investigated the frequencies of the AGTR2 alleles in 2178 Caucasian athletes and 1220 control subjects. The frequency of the AGTR2 C allele was significantly higher in male and female endurance athletes compared with power athletes (males, 62.7 versus 51.7%, P = 0.0038; females, 56.6 versus 48.1%, P = 0.0169) and control subjects (males, 62.7 versus 51.0%, P = 0.0006; elite female athletes, 65.1 versus 55.2%, P = 0.0488). Furthermore, the frequency of the AGTR2 A allele was significantly over-represented in female power athletes (51.9%) in comparison to control subjects (44.8%, P = 0.0069). We also found that relative maximal oxygen consumption was significantly greater in male endurance athletes with the AGTR2 C allele compared with AGTR2 A allele carriers [n = 28; 62.3 (4.4) versus 57.4 (6.0) ml min(-1) kg(-1); P = 0.0197]. Taken together, these results demonstrate that the AGTR2 gene C allele is associated with an increased proportion of slow-twitch muscle fibres, endurance athlete status and aerobic performance, while the A allele is associated with a higher percentage of fast-twitch fibres and power-oriented disciplines.
