A Comparative Study On The Kinematics And Electromyography Characteristics Of Backcourt Backhand High Clear Techniques Of Men Badminton Athletes

Research purposes: The research analyzes the kinematics and electromyography characteristics of backcourt backhand high clear techniques of men badminton athletes at different levels in order to obtain the sports characteristics of athletes at the master level and the second level,and the shortcomings of the latter for providing reference for the training of athletes in level two and other levels.Research methods: The paper uses the analysis system of APAS three-dimensional image and the test system of MEGAWIN surface electromyography to test the backcourt backhand high clear techniques of men badminton athletes,and makes a synchronizing test based on kinematics and surface electromyography.By collecting the image data,muscle strength parameters and EMG parameters of each muscle group during motor process,the study analyzes the kinematics characteristics and electromyography characteristics of backcourt backhand high clear techniques of men badminton athletes at different levels.Research findings:(1)For the master-level athletes,the angle of the left knee joint is139.3 °in the warm-up stage,the placement of the racket is 1.19 m and the racket speed is 0.06 s in the swing stage,and the torso torsion angle is 52.3°in the stroking stage,,which indicates that they could store more elastic potential energy to hit the ball better.(2)The contribution rate of muscles in each stage for the master-level athletes: in the warm-up stage,the contribution rate of the musculus biceps brachii is 56%;in the swing stage,the contribution rate of musculus extensor digitorum is 31%;and in the following stroking stage,the contribution rate of the musculus biceps brachii is 74%.(3)For the second-level athletes,the angle of the right lower extremity hip joint is 106.8 °,the knee joint angle is 96 °,and the angle of ankle joint is 110.8 °in the warm-up stage.And the angle of elbow joint is 139.3 °during the swing stage and the stroking stage.(4)The contribution rate of muscles in each stage for the second-level athletes:the contribution rates of the deltoid bundle in the warming-up stage,the swing stage and the stroking stage are respectively 28% and 43% and 38%.Conclusions:(1)The master-level athletes push the ground more fully in the warming-up stage.In the swing stage,the racket has a further displacement with less movement time.In the stroking stage,the torso angle of the torso is slightly larger so that more elastic potential energycan be stored,which is more helpful to hit the ball.(2)The contribution rate of muscles at each stage of master-level athletes: in the warming-up stage,the musculus biceps brachii has the maximum contribution rate;at the stage of swing and stroking,the largest contribution rate goes to the musculus extensor digitorum;in the stroking stage,the musculus biceps brachii has the maximum contribution rate.It shows that the technical movements of the master-level athletes are more fluent in each stage;their bodies are more relaxed before the stroking,their movements in the stroking stage are fluent and in the stroking and finishing stage,they are more relaxed.(3)For second-level athletes,the stride amplitude of the right lower extremity is too large in the warming-up stage,which affects the stability of the center of gravity.In the swing and stroking stages,the elbow joint is not fully stretched,which affects the hitting point position and energy transfer.(4)The contribution rate of muscles at each stage for the second-level athletes: in the warming-up,the swing and stroking stages,the contribution rate of the deltoid bundle is the utmost.It shows that there is serious tension in the shoulder joint of second-level athletes in the whole process of the technical action,which is not conducive to fluent stroking and return preparation.