Investigation of Heart Rate Variability of 14-18 Aged Swimmers: Loading and Recovery In Different Swimming Styles In Short Distance (50 M)

The present study aimed to compare the effects of different swimming styles (freestyle, backstroke, breaststroke, butterfly) on heart rate variability (HRV) before, during and after 50m sprint performance. In the literature, some studies directly compare the differences in recovery time depending on swimming distance. However, to our knowledge, no study investigates the differences in recovery time according to swimming style; this study aims to fill this gap. Swimmers participated in the study as volunteers (mean age 15.4±1.2 years; height 175.3±6.8 cm; weight 64.9±7.6 kg). The study was implemented with a randomized crossover design and each participant completed the HRV measurements by swimming 50 m at maximum speed in four different swimming styles. Time-domain (RR-SDNN-RMSSD) and frequency-domain (VLF-LF-HF) data of HRV were collected before (Pre-test), during (Test), and immediately after (Post-test) the 50m swim with the Polar V800 device. The data were analyzed by two-way ANOVA test (3-time x 4-intervention). From the time domain data of the participants, the interaction of time and style RR (Fs*t=2.670, η_p^2=0.08), SDNN (Fs*t=2.251, η_p^2=0.07) was found to have a statistically significant difference, but RMSSD (Fs*t=0.746, η_p^2=0.01) was found to have no statistically significant difference. From the frequency domain data, time and style interaction of VLF (Fs*t=2.590, η_p^2=0.08), LF (Fs*t=4.271, η_p^2=0.13), HF (Fs*t3.156, η_p^2=0.10) were found to have statistically significant differences. The differences in the results vary depending on the technical requirements of the swimming styles and their demands on the energy systems. The fact that each style utilizes different muscle groups and metabolic pathways to different degrees is one of the main reasons for these variations in recovery. In short-distance (50m) swimming performance in freestyle, backstroke, breaststroke, and butterfly swimming styles, the HRV before, during, and after swimming at maximum speed may have different effects on time and frequency domain parameters. In conclusion, the swimming style's technical challenges and predominant energy systems should be considered during training planning, ensuring an appropriate balance of loading and rest that accounts for recovery time and the physiological demands of each style.