en آسیب شناسی ورزشی و حرکات اصلاحی Sport injury and corrective exercises پژوهشي Research <div style="text-align: justify;"><strong>Purpose</strong>: The present study examined selected kinematic characteristics analysis of knee and ankle joints during block jump in elite junior volleyball players.<br> <strong>Methods</strong>: Thirty male junior elite volleyball players (Mean&plusmn;SD age: 18.14&plusmn;1.12 y, height: 197.10&plusmn;3.16 cm, sports history: 4.39&plusmn;0.95 y, & weight: 771.20&plusmn;59.83 N) participated in this study. A time-synchronized 5-camera sampling at 100 Hz was used to determine the Three Dimensional (3D) coordinates of markers. Kolmogorov-Smirnov test, linear regression, and magnitude of coefficient were used in SPSS to analyze the obtained data (P<0.05).<br> <strong>Results</strong>: The Mean&plusmn;SD height of block jump was 45.5&plusmn;2.06 cm, and the Mean&plusmn;SD angles of knee and ankle flexion were 93.37&plusmn;4.75 and 21.25&plusmn;2.98 cm, respectively. Moreover, there was a negative relationship between knee and ankle flexion angle and block jump height (-0.051, -0.054, respectively) (P<0.05). However, smaller knee flexion angles had more negative effect on block jump height (0.741) (P<0.05).<br> <strong>Conclusion</strong>: The study results could be used by coaches as a simple tool in jumping performance among junior volleyball players. The obtained data could also be beneficial in the efficient control of applied training procedures.</div> Biomechanics, Block jump, Volleyball, Knee, Ankle 161 168 http://ptj.uswr.ac.ir/browse.php?a_code=A-10-416-1&slc_lang=en&sid=1 Ali Fatahi fattahiali81@gmail.com 0000-0002-8863-4061 Yes Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, Central Tehran Branch, Islamic Azad University, Tehran, Iran. Heydar Sadeghi ry_ot83@yahoo.com 0000-0001-6563-9882 No Department of Sport Biomechanics, Kharazmi University, Tehran, Iran. Razieh Yousefian Molla raziehyousefian@yahoo.com 0000-0002-1527-7737 No Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, Central Tehran Branch, Islamic Azad University, Tehran, Iran. Mitra Ameli amelimitra@gmail.com 0000-0002-4876-3037 No Department of Physical Education and Sport Sciences, Payam-e-Noor University, Tehran, Iran.