The Influence Of Plyometric On The Lower Limbs’ Ability Of Junior Speed Skating Athletes

By conducting comparative experiments,this paper is to explore the influence of compound training of rapid expansion and contraction on the lower limb movement ability of juvenile speed roller skaters,so as to provide strong theoretical support for the training methods of professional teams,clubs and coaches engaged in juvenile speed roller skaters.This paper has mainly employed three methods: literature review,mathematical statistics and experimental methods.Sixteen juvenile speed roller skaters were selected from Beijing Le Xiang and Kuai Xingzhe roller skating clubs as the experimental subjects.They were randomly divided into two groups: the experimental group(n=8)and the controlled group(n=8).Both the experimental group and the controlled group have received 2 weeks’ adaptive training,the experimental group was trained by rapid stretching and compound training for 8weeks.At the same time,the controlled group was trained in conventional strength training.By using traditional testing tools,this paper has measured lower limbs’ four indexes of explosive force from different dimensions both before and after the experiment.They are standing long jump,vertical jump in place,left and right jump of one foot.It also tested four speed dimensions of skating roller in short distance speed sprint: 10 meters sliding sprint,20 meters sliding sprint,30 meters sliding sprint,50 meters sliding sprint.Y-balance test,also named as Y-balance,have tested 6indexes of left and right foot’s support of lower limbs.They are right anterior side,right posterior medial side,right posterolateral side,left anterior side,left posterolateral side and left posterolateral side.Sensitive test of speed roller skating has been used to test 2 indicators: Illinois sensitive test and corner intersection step.The research results can be drew as follows:(1)when testing the explosion force of lower limbs,there were significant differences between the experimental group and the control group in standing long jump,vertical jump in situ and left and right jump with one foot(P < 0.05)after the experiment;and in the standing long jump and vertical jump touch height in place,the experimental group’ results were significantly increased(P < 0.05);and in the left and right jumps of one foot,the performance of participants were more significantly increased(P < 0.01);(2)after the experiment,there was a significant difference between the pretest and post test in speed roller skating sprint test of 30 m and 50m(P < 0.01),and participants of experimental group made great progress after the intervention(P < 0.01);(3)in the post test of Y-balance,comparing with controlled group,experimental groupers make significant progress in the right anterior side,right posterolateral side,right posterolateral side,left anterior side,left posterolateral side and left posterolateral side(P < 0.05);(4)in the Illinois sensitivity test and the corners intersect,the sliding ability of experimental participants and controlled group has significant differences between pretest and posttest(P < 0.05),in which the experimental group had more significant improvement of intersection steps of curves(P < 0.01),while there was no significant difference between the control group before and after the experiment(P > 0.05).Therefore,the conclusions of this paper are that:(1)the compound training of rapid expansion and contraction can effectively improve the explosive force of lower limbs of juvenile speed roller skaters,and then improve the athletic performance on the competition;(2)the compound training of rapid expansion and contraction can not significantly improve the skidding-accelerating ability of juvenile speed skaters in short distance of 10 m and 20 m,but in long distance of 30 m and 50 m.(3)compound training of rapid expansion and contraction can improve the balance and stability of the lower limbs of juvenile speed roller skaters.According to the data analysis of y-balance,the athletes’ one-foot support is more stable and can increase the sliding efficiency.(4)the compound training of rapid expansion and contraction can improve the skidding ability of the juvenile speed roller skaters at the intersection of corners,making the team members more agile and efficient in the corners and shortening the time of corners.