Kinematics And EMG Characteristics Of Backcourt Overhead Smash Techniques Of Male Badminton Players At Different Levels

Objective:In view of the fact that when observing the daily badminton training,it is found that the difference in the speed of the first and second level group athletes in the in situ backcourt overhead smash is not too large,the batting effect is relatively good,and the backcourt overhead smash speed of the second-level group athletes in the moving state is far less than that of the first-level group athletes,so this paper analyzes the kinematic and muscle power characteristics of the backcourt overhead smash technique of male badminton players at different levels in situ and moving states respectively from the perspective of kinematics and surface electromyogram,to demonstrate whether there is a difference between the two groups of athletes in situ state.As well as the key factors affecting the speed and quality of the second-level group athlete’s backcourt overhead smash in the moving state,it points out the shortcomings and links that need to be improved,so as to provide a basis for the second-level group athletes to carry out special technical training and improve the backcourt overhead smash technology.Methods:This research mainly used the literature method,test method,mathematical statistics method and other research methods,and 10 male badminton players of Shanghai University of Sport were tested,including 4 athletes in the first-level group and 6 athletes in the second-level group.The 3D infrared motion capture system of Chingmu and the NORAXON electromyography test system were used to synchronize the backcourt overhead smash technology of badminton players,collect the kinematic indicators of badminton athletes and related muscle electromyography activity parameters,and analyze the kinematic characteristics such as joint angle,joint angular velocity,and center of gravity height of male badminton athletes at different levels to complete the backcourt overhead smash technique,as well as the characteristics of IEMG and contribution rate.Results:In situ state,there was no significant difference in the time it took the first-level group athletes and the second-level group athletes to complete the action;in the moving state,there was a significant difference in the time consumption between the first-level group athletes,and the total time spent on the completion of the action by the first-level group athletes was less than that of the second-level group athletes.In situ state,there was no significant difference in the height of the center of gravity of the first-level group athletes and the second-level group athletes at the time of racketing,the time of scratching the back,and the moment of hitting the racket;in the moving state,there was a difference between the time of hitting the back and the moment of the racket touching the ball,and the height of the center of gravity of the players in the first-level group athletes was higher than that of the second-level group athletes.In situ state,only the shoulder joint angular velocity was statistically significant in the kinematic data of the first-level group athletes and the second-level group athletes,and there was no significant difference in the rest of the indicators;in the moving state,there were statistically significant differences in the knee angular velocity,spinal roll angle,torsional angle of the trunk,shoulder angle and angular velocity,elbow angle,wrist angle and ball speed between the first-level group athletes and the second-level group athletes.In situ state,the muscle integral emulsion values of the first-level group athletes and the second-level group athletes were only statistically significant differences in biceps and pectoralis major muscles,and there was little difference in muscle contribution rate;in the moving state,there was a statistically significant difference between the trapezius and latissimus dorsi,and the muscle contribution rate was not much different.Conclusion:1.In the analysis of the characteristics of the backcourt overhead smash in situ state,only the shoulder joint angular velocity of the first and second level athletes has a significant difference in the angular velocity of the shoulder joint,and the rest of the indicators are not much different;while there are more significant differences between the two groups of athletes in the moving state.Indicating that the the second-level group athletes decrease the speed of the upper limbs and the ability to control the joint angle through the power transfer of the lower limbs and the trunk,which affects the batting effect.2.The first-level group athletes increase the spinal roll angle during the movement to obtain a wider range of bats,while the second-level group athletes have a small spinal roll angle and a torso torsion angle during the movement,the strength of the trunk muscle group is weak,and the rotation is insufficient,resulting in passive batting to reduce the ball speed.3.In the analysis of SEMG,in the moving state,the first-level group athletes have a complete power transmission of each link of the body when completing the entire technical action,and the second-level group athletes rely more on the strength of the upper limb muscles,and the cooperation between muscle work is not reasonable enough,reducing the kinetic energy when swinging and hitting the ball,and reducing the ball speed.