Analysis On Technique Movement Kinematics Of Down Force Assault And The Characteristics Of Muscle EMG In The Core Region Of Different Levels Badminton Players

Objective: This paper analyzes the technique movement of down force assault and the characteristics of muscle EMG in the core region of different levels badminton players,discusses the characteristics and differences between the first-and second-class badminton players,and points out the shortcomings that secondary players need to overcome.It provides special technical training for the second-class players and also provides a basis for the low-level players to learn from the high-level players to improve the skill of down force assault.Methods:In this paper,16 excellent male badminton players in Shenyang Sport University are applied as the experimental objects,8 in the first-class group and 8 in the second-class group.Using "APAS three-dimensional image analysis system" and "MEGAWIN EMG test system" to carry out synchronous experiments on badminton players' down force assault skill in order to collect the kinematic indexes of players and the parameters of muscle EMG activity in the core region.Then it analyzes the kinematic and EMG graphic characteristics of different levels of male badminton players' down force assault actions.Results: There was a significant difference in the total time that need to complete the technical movements between the two groups,0.7s for the first-level group and 0.9s for the second-level group.In the preparation stage,there was a significant difference in the joint angle of the right lower limb between the two groups,and so was the joint speed of the right upper limb.The difference in the integral muscle value of the muscle measured in the experiment was significant,but the contribution rate was not obvious.In the backswing stage,there was a significant difference in the joint velocity of lower limb and right upper limb between two groups,and a significant difference in the joint angle of right upper limb.The integrated EMG has the largest median value in the complete technical movement.The lower limb movement speed in the first-class group was faster than that in the second,and the wrist joints of the upper limbs buckled in a short time.During the assault stage,there was a significant difference in the angle between the right upper limb and the knuckle of the two groups players.The velocity of each joint reached the highest.The angle of the ankle joint was the smallest at this moment.The hips,knees,and ankles initially move forward and upward and transmitted elastic potential energy to the upper limb joint;In the swing stage,there was no significant difference in the joint angle and speed of the two groups players,so was the muscle contribution rate of the core region;And the torsion angle of the trunk was significantlydifferent in each stage.Conclusions:(1)The first-class group can complete the pedaling and stretching more quickly than the second-class group,and the vertical upward speed is more sufficient than the second.The ankle joint transfers the elastic potential energy at a faster speed to extend the knee and transfer it from the torso to the arm to swing and hit the ball.(2)In the backswing stage,the core region muscle activity accounts for the largest proportion in the total discharge volume.The core region muscle rapidly rotates around the longitudinal axis of the body to contract with full force,and the elastic potential energy is maximized.In the batting stage,the discharge volume of the two groups players accounts for the smallest proportion.At the moment of hitting the ball,the main generating muscles are concentrated in the arm.(3)The first-class group takes less time than the second,and the first-class group hit the ball faster with the hand that hold the racket.The second level group also need to strengthen the movement standard,speed up the initial speed of getting the ground,select higher hitting points,and speed up the rotation speed to fully recruit the core area muscles to maximize the release.