Competitive Study Of Kinematics And Muscle Activity Between Superior And Amateur Table Tennis Players During Backspin Backhand Loop

Objective: Backspin backhand loop is the critically skill among various techniques in table tennis.The purpose of this study was to investigate the differences of kinematic and muscle activity of lower limb during table tennis backspin backhand loop between superior and amateur players.Methods: Twenty male table tennis players(ten with superior(trained years: 13.4±1.2years)and ten with amateur players(played:3±1.9years))participated in this test,without history of exercise training and free from any diseases or injuries.Subjects were asked to perform crosscourt backhand loop against the backspin ball with maximal power.The Vicon motion analysis system was used to capture kinematics data and the MEGA ME6000 system was used to capture electromyoqraphic signals(average electromyography,mean power frequency,median frequency).The repeated measures ANOVA with independent sample T test from SPSS 17.0 were taken to analyze the significance among superior and amateur players,with significance level at 0.05.Results: The motion was divided into two phases as backswing and swing,the flexion and extension of the superior players and amateur players' joints angle tendencies showed a significant difference.Compared to amateur players,the superior players presented larger eversion angle to the ankle,flexion to the knee and hip at the beginning moment of backswing(P<.001),and much faster rate of flexion angle change to the ankle,knee and hip(P<.001).the coefficient of multiple correlation values of amateur players are all beyond 0.9,indicating pretty high similarity of curves of their joints angle change during performing backspin backhand loop,forming a dynamic shape,while the curves of amateur players tend to locate the range of moderate similarity(the coefficient of multiple correlation from 0.5 to 0.75).In the electromyographic signal test,the superior players presented smaller standardized average electromyography of lower limb muscles in the backhand backspin loop than that of amateur players,in addition,the maximum of each muscle activation of superior players were smaller than that of amateur players and mean power frequency of the lower limbs of the superior players is greater than that of the amateur players in the whole technical movement of the backhand backspin loop.Conclusions and Implications: Compared to the amateur players,the superior players prepare more fully,which can lead to more quickly shot and earlier reach the location of the swing conducing to adjust the swing action,the superior players could complete the backhand backspin loop in a less time,what's more,the speed rate of joints angle change were faster than that of amateur players,which can lead to more rapidly transmission of power from the lower limb to the trunk to the upper limb.Compared to amateur players,normalization AEMG of superior players on both sides of the lower limb muscle showed generally smaller,in addition,the maximum of each muscle activation of superior players were smaller than that of amateur players and MPF of the lower limbs of the superior players is greater than that of the amateur players in the whole technical movement of the backhand backspin loop,it reflected that superior players can efficient complete of this professional technical action,functional savings.