KINEMATIC AND KINETIC EVALUATION OF JUMP-LANDING TASK IN VOLLEYBALL DEFENSE: IMPLICATIONS FOR ACL INJURY RISK ASSESSMENT

The aim of this study was to evaluate the biomechanics of jumping and landing in defense between beginner and professional volleyball players. 10 professional volleyball players from Iranian leagues and 10 beginners with less than 2 years of training experience participated in this study. Selected kinetic and kinematic variables in jump and landing movement in 5 tasks of volleyball defense was analyzed. There were no significant differences between beginners and professional groups in different types of jumping and landing in the phase of preparation, jumping and landing in the variables of ground reaction force in different directions except the variable YP1 in the side stepping to the left (P = 0.029) and loading rate. The results also showed that the knee flexion angle at the moment of landing in all jumps was significantly higher in professional volleyball players than in the beginner group. The difference between the groups in maximum knee flexion in the landing phase was also significant in all jumps except the side stepping to the left (p <0.05). Professional volleyball players have a lower risk of ACL injury than beginner volleyball players. As a result, to reduce the risk of ACL injury in beginners, it is necessary to pay attention to landing exercises and focus on increasing the flexion angle.