R577X OF THE ACTN3 GENE AS PREDICTOR OF PHYSICAL PERFORMANCE IN ULTRAMARATHON RUNNERS

The frequency of the ACTN3 polymorphism in Brazil: a systematic review and meta-analysis

BACKGROUND

The ACTN3 gene encodes the protein alpha-actinin-3, which is crucial for fast-twitch muscle fibers, contributing to rapid and forceful contractions. The distribution of these genotypes and their impact on sports performance in Brazilian populations are not well-documented. This study aimed to determine the allelic and genotypic frequency of the ACTN3 R/X polymorphism in Brazil and its association with sports performance.

METHODS

A systematic review was conducted, including studies sourced from PubMed, Scielo, LILACS, LIPECS, Coleciona SUS, CUMED, BINACIS, IBECS, and MEDLINE databases, resulting in 42 studies included. The quality of these studies was assessed using the Strengthening the Reporting of Genetic Association (STREGA) guidelines.

RESULTS

Among all the 8,746 participants, 35.2% had the RR genotype, 46.2% had the RX genotype, and 18.6% had the XX genotype. Regarding allelic frequency, 58.3% were R allele carriers, while 41.7% were X allele carriers. Meta-analysis showed that there was no consistent association between the ACTN3 genotypes and sports performance, although some data suggested potential benefits in athletic performance.

CONCLUSION

This study revealed that the RX genotype of the ACTN3 R577X polymorphism is the most prevalent in Brazil, followed by the RR and XX genotypes. While the R allele was more frequent, the meta-analysis did not confirm a consistent association between ACTN3 genotypes and sports performance, suggesting that other genetic and environmental factors contribute to athletic success.

Increased prevalence of the null allele of the p.Arg577Ter variant in the ACTN3 gene in Brazilian long-distance athletes: A retrospective study

INTRODUCTION

The phenotypic consequences of the p.Arg577Ter variant in the α-actinin-3 (ACTN3) gene are suggestive of a trade-off between performance traits for speed and endurance sports. Although there is a consistent association of the c.1729C allele (aka R allele) with strength/power traits, there is still a debate on whether the null allele (c.1729T allele; aka X allele) influences endurance performance. The present study aimed to test the association of the ACTN3 p.Arg577Ter variant with long-distance endurance athlete status, using previously published data with the Brazilian population.

METHODS

Genotypic data from 203 long-distance athletes and 1724 controls were analysed in a case-control approach.

RESULTS

The frequency of the X allele was significantly higher in long-distance athletes than in the control group (51.5% vs. 41.4%; p = 0.000095). The R/X and X/X genotypes were overrepresented in the athlete group. Individuals with the R/X genotype instead of the R/R genotype had a 1.6 increase in the odds of being a long-distance athlete (p = 0.012), whereas individuals with the X/X genotype instead of the R/R genotype had a 2.2 increase in the odds of being a long-distance athlete (p = 0.00017).

CONCLUSION

The X allele, mainly the X/X genotype, was associated with long-distance athlete status in Brazilians.

EFFECTS OF FUNCTIONAL TRAINING ON PROPRIOCEPTION IN SPORT ATHLETES

ABSTRACT Introduction Physical training is a well-known training method in competitive sports. However, in the majority of the physical training classes, the focus is still on the traditional exercises of physical conditioning as strength, speed, resistance, etc., directed for young athletes that are in the growth and development phase, without a literary base to assure actual effectiveness in the load increases for the athletic performance facing the risks in the athletes’ physical proprioception. Objective Explores the effect of functional training on the physical sensibility of sports athletes. Methods The data collection method is used in the daily training of six notable athletes in a district sports school: judo, martial arts, wrestling, tennis team, swimming team, and table tennis team, adding the functional training protocol in body movement. Results The average performance of the groups before and after the experiment was collected and confronted, the difference test was performed, and the test result found P>0.05. The athletes in the experimental group not only improved the footwork speed and physical coordination, the movement speed of the footwork and the speed of the connection between movements increased significantly in the sixth week, reflecting more excellent stability and motor coordination in the movements. Proprioception is one of the essential sports qualities of the human body; it is directly related to physical qualities such as speed and strength and is also closely related to the different neural pathways. Conclusion Functional training can improve athletes’ physical flexibility and motor coordination; it can also stimulate body proprioceptors, increase athletes’ confidence, and make training more efficient and effective. Evidence level II; Therapeutic Studies - Investigating the results.