The Effect of a Twelve-week Endurance Swimming Training on Structural and Functional Features of Heart in Inactive Male Adolescents

Background and Aims: Exercise plays an essential role in improving cardiovascular function. Due to the increasing tendency of children and adolescents to swim, this study aimed to investigate the effect of twelve weeks of endurance swimming training on structural and functional characteristics of the heart of inactive adolescents Methods: The present study was quasi-experimental with a pre-test, post-test design. Thirty inactive male students with an age range of 13 to 15 years (age 14.1±1.7 years, height 164.5±5.26 cm, and weight 54.4±6.2 kg) were selected voluntarily. Then They were non-randomly divided into experimental (n=15) and control (n=15) groups. The subjects in the experimental group performed endurance swimming exercises for 12 weeks and three sessions per week with an intensity of 60% of maximum heart rate. Also, the duration of each training session was 75 minutes. The echocardiography measured the left ventricular end-diastolic dimension, left ventricular end-systolic diameter, septal wall thickness, stroke volume, and ejection fraction before and after the exercise protocol. Shapiro-Wilk test, paired t-test, and independent t-test were used to analyze the obtained data at a significant level of P0.05). No significant change was observed in the control group in any of the measured indicators compared to the baseline (pre-test). Conclusion: The present study results showed that 12 weeks of endurance swimming training could have beneficial effects on left ventricular end-diastolic dimension and stroke volume of the heart of inactive adolescent boys by increasing cardiac preload.