Maryam Zare Mojtahedi - Department of sports Biomechanics, Central Tehran Branch, Islamic Azad university, Tehran, Iran
Razieh Yousefian Molla - Department of Physical Education and Sports Sciences, Faculty of Physical Education and Sports Sciences, Islamic Azad university of Karaj, Karaj, Iran
Ali Fatahi - Department of sports Biomechanics, Central Tehran Branch, Islamic Azad university, Tehran, Iran

Careful analysis of demographic characteristics is required during the implementation of the net defense skill on kinetics because it can increase the performance of this skill. The aim of this study was to analyze the relationship between jump height and demographic characteristics of young volleyball players while performing block jump on kinetics..۲۱ young male volleyball players participated in this study as subjects selected by sampling method for the title of elite players. Each player performed block jump on the force plate with the highest jump height three times, and from the average jump rate obtained from the average of ۱ (transfer), to do the calculation and analysis of question. In this study, the demographic industries of height and weight of the subjects were taken. The height of each subject is determined by a wall gauge without shoes and the weight is determined by the Fz force plate component when the person is statically placed on this instrument. For statistical analysis of the present study, SPSS software version ۲۲ was used. Shapirvillek test was used to test the normality of the data and descriptive statistics (mean and standard deviation) and then linear one-way regression statistical method was used to determine the load and order of factors between the jump height with the demographic characteristics of height and weight. Among the variables of height and weight, they did not show any significance with the jump height, but several times height had a higher factor load than the weight on the jump height. Demographic characteristics should be considered as appropriate indicators to increase the performance of jumping and landing skills of elite volleyball players, and it is recommended to coaches, players and volleyball specialists to evaluate different performances from biomechanics and study them in order to achieve success

Jump height, Demographic characteristics, Block jump, Volleyball