en روانشناسی ورزشی و شاخه‌های وابسته بدان Sport Psychology and its Related Branches مقاله اصیل Original Article <div style="text-align: justify;"><strong>Background. </strong>A biofeedback program receives attention as an intervention program for athletes to regulate their psychological state. Objectives. The purpose was to apply for a heart rate variability (HRV) biofeedback training program and validate its effectiveness for racket sports players.<br> <strong>Methods.</strong> The participants were eight elite sport&nbsp;athletes (three men and five women): five squash players and three tennis players. The HRV biofeedback training program consisted of ten sessions in which the participants performed paced breathing for 10 minutes (e.g., 5-second inspiration and 5-second expiration). The means and standard deviations of the collected data were calculated, and the Wilcoxon signed-rank test was performed using SPSS windows 18.0.<br> <strong>Results. </strong>Changes in HRV by the biofeedback training were significant. Standard Deviation of Normal to Normal (SDNN; Z = -2.38, p = 0.017) in time domain and Low Frequency (LF, Z = -2.52, p = 0.12) and the ratio of LF to High Frequency (HF; Z = -2.52, p = 0.12) in frequency domain were increased.<br> <strong>Conclusion. </strong>The present study provides empirical results needed to expand HRV biofeedback training research for the performance enhancement program of athletes.</div> Heart Rate Variability, Biofeedback Training, Sport Performance 0 0 http://aassjournal.com/browse.php?a_code=A-11-1368-1&slc_lang=en&sid=1 Sang-Hyuk Park sang4@kspo.or.kr 10031947532846008204 10031947532846008204 No Department of Sport Science, Korea Institute of Sport Science, Seoul, South Korea Seunghyun Hwang hwangsh@knu.ac.kr 10031947532846008205 10031947532846008205 Yes Department of Leisure Sport, Kyungpook National University, Sangju, South Korea Sang-Mi Lee s2301m@hanmail.net 10031947532846008206 10031947532846008206 No Department of Sport Science, Korea Institute of Sport Science, Seoul, South Korea