A Comparative Study on the Effect of ACTN3 Gene Polymorphisms (RR, RX, XX) on Aerobic and Anaerobic Energy Indicators among Handball Players

Abstract

The importance of this study lies in its aim to compare handball players according to the ACTN3 gene polymorphisms (RR, RX, XX) in selected indicators of aerobic and anaerobic energy, in order to explore the relationship between genetic structure and physiological efficiency, and to determine whether these gene patterns contribute to explaining differences in physical performance among players, The study aimed to identify the ACTN3 gene polymorphisms (RR, RX, XX) in a sample of handball players, measure selected aerobic and anaerobic energy indicators, and compare these indicators among the three genotypes. The researchers adopted the experimental approach, as it was suitable for the nature of the research problem, specifically using the quasi-experimental design with three groups based on the genetic classification of players, The research population consisted of (30) young male handball players from the National Center for Sports Talent Development in Diyala Governorate. The research sample was selected randomly and included (22) players. The field procedures included conducting laboratory and field tests: the 40-, 50-, and 60-yard sprint tests to assess short-term anaerobic power, the step test to assess lactic (anaerobic) capacity, and the Harvard step test to assess aerobic capacity, The practical application was carried out over two consecutive days, Wednesday and Thursday (October 8–9, 2025), in the indoor sports hall at the Diyala Sports Club in Baqubah, The results revealed, after analysis and discussion, significant differences among the three genotypes (RR, RX, XX) in both aerobic and anaerobic performance indicators of the handball players, confirming the influence of ACTN3 gene polymorphism on variations in physical and physiological performance, The researcher recommends using ACTN3 genotyping as one of the indicators for sports talent selection, particularly in team sports such as handball, to determine the most suitable training direction (endurance – speed – power). Furthermore, it is recommended to design specialized training programs that take into account genetic individual differences, aiming to develop aerobic or anaerobic capacities according to the player’s genetic profile for optimal performance efficiency. The study also recommends utilizing genetic analysis results in early talent identification to guide young athletes toward sports or playing roles that match their genetic and physiological characteristics.