The purpose of this study is a comparison among th
effect of three models of plyometric training (depth
jump) on electromyograph indexes (Amplitude and
frequancy) of Rectus femoris and Vastus medialis
muscles in 16-18 year old athletes. In this study, 45
students from physical education and sport sciences
high school were selected randomly and divide into 3
groups of 15 after perfroming the ability tests for
participating in depth jump training. All 3 groups
participated in 16 sessions depth jump training, it
should be noted that the method of depth jump training
was different for each group.The subjects of group A
exercised bouncing Depth Jumps (BDJ) or (DJ- H/T),
group B did counter movement jumps (CMJ) or
(DJ-H) and as for-groupC the same exercises of group
B were performed wearing weight jackets (CMWJ) or
(DJ-W/H). The height of the box and vertical jump
were equal for all groups (40& 70 CM .An EMG was
used for measuring the electromyography indexes.
This mesurements were done in three phase before
training, in the middle of training ( after the 8th
session) and after training. The results of the variance
phase showed that regarding the aimed variables only
the changed in group A that were related to the
electromyography indexes were significant from a
statistical point of view and there was no significant
difference seen in this. index between the other
groups during the above mentioned phase
analysis test (ANOVA) in comparison with the
average of electromyography indexes ( amplitude and
frequancy of the muscles in this study) in the 3 study