THE EFFECT OF 50 M SPRINT SWIMMING ON HEART RATE VARIABILITY IN 13-14 YEAR-OLD BOYS

The aim of this study was to assess the effect of 50 m sprint swimming on heart rate variability (HRV) via a five-minute ECG recording in 13-14 year-old boys. Thus, the effects of similar physical exertions on the heart rate can be investigated. Ten male swimmers participated voluntarily in this study. The mean age, height, body weight and percent body fat were 13.40 ±.52 yr, 168.70 ± 8.35 cm, 59.56 ± 11.86 kg and 14.51 ± 5.69 % respectively. Body composition measurements were completed by using Avis 333 plus analyzer (Korea). HRV measure was taken with five-minute electrocardiography recording during pre and posttest by Omegawave 800 (Oregon, USA). SPSS (version 16) was used for statistics. Shapiro Wilk test for normality, Wilcoxon test and Paired-Samples t-Test for comparison of mean differences were used and 0.05 alpha value was set for significance. There were statistically significant differences between pre and post HRV measurements. While activity of vagus regulatory mechanism was significantly lower for post exercise (p 0.05), activity of sympathetic regulatory mechanism was higher (p 0.05). Pre-test results showed that time-domain parameters coded as SDNN, SDSD, RMSSD were statistically higher (p 0.05) when compared with the post-test scores. In frequency-domain parameters, there were statistically significant differences in HF, LF, LF/HF and TP except for VLF scores for pre and posttest comparisons HF and LF scores were higher in pre-test (p 0.05) whereas LF/HF and TP scores were higher in post-test (p 0.05). It can be concluded that an activity of 50 m sprint swimming can affect sympathovagal balance. A short and intensive physical activity can cause an increase in sympathetic activity