Vol. 7, Issue 2, Part B (2025)

This study investigates the relationship between ACTN3 gene polymorphism (RR, RX, XX) and both functional indicators and 400-meter freestyle performance in junior swimmers of the Iraqi national team. Seventeen male swimmers were genotyped and divided into three groups based on their ACTN3 variant. Functional variables measured after exertion included systolic and diastolic blood pressure, heart rate, and oxygen saturation. A 400-meter freestyle swim test assessed endurance performance. The results showed statistically significant differences among the genotypes (p<0.05), with the XX group outperforming the RX and RR groups in swim time and physiological efficiency. The XX genotype demonstrated lower post-exercise heart rate and blood pressure, and higher oxygen saturation, indicating superior aerobic capacity and recovery. These findings suggest that the ACTN3 gene plays a meaningful role in endurance performance and physiological responses in swimming. The study highlights the potential of incorporating genetic testing in talent identification and training specialization strategies for young athletes.