Ali Fatahi - Department of Sports Biomechanics, Faculty of Physical Education and Sports Science, Islamic Azad University of Central Tehran Branch, Tehran, Iran
Razieh Yousefian Molla - Department of Sports Biomechanics, Faculty of Physical Education and Sports Science, Islamic Azad University of Central Tehran Branch, Tehran, Iran
Mitra Ameli - MSc in corrective Exercises, Athletic & Clinical Research Center of Pouyesh Setaregan Salamat, Tehran, Iran

The purpose of this study was to examine kinematic analysis of knee and ankle joints during Block jumpskill in elite junior volleyball players and investigate the relationship between knee and ankle flexion anglecontributing to vertical jump in volleyball players. Thirty male junior elite volleyball players participated inthis study. Absolute angles of the Knee and ankle were determined by a time synchronized 5 camerasampling. Linear regression were used to identify data normality and possible relationship between kneeand ankle joint angle with block jump height as well as magnitude coefficient of each variable respectively(p<0.05). According to results, there are negative relationship between knee and ankle flexion angle andBlock jump height respectively. Coaches and players should pay attention more to the technique of blockjumping using suitable value of knee and ankle flexion angles with respect to performance optimization andinjury preventions.

Biomechanics- Block jump- volleyball- Knee- ankle