| Research purposes: In this study,the three-dimensional high-speed image capture system and surface electromyography acquisition system were used to test the backhand net step and pick technique of male second-level athletes and special students in badminton.This paper analyzes the complete action process of the step-pick ball,explores the kinematics and muscle force characteristics of the step-pick ball technique in front of the badminton backhand net,and also provides a theoretical and practical basis for college teachers or coaches in their daily teaching and training.Research methods: 1.Document method.2.Test method:（1）Research objects: 8second-level badminton athletes and 8 students in special class of Xi’an Institute of Physical Education’s backhand net kicking technique.（2）Test plan: The subjects stand in the center of the court in a ready posture,the ball machine will serve the ball in the designated area,and after the ball is served,the athlete will use the backhand net to step forward and pick the ball to the designated area in the opposite backcourt.The test recorded the movement process of the subjects in five stages,including starting,moving and positioning,leading the racket,swinging the racket and hitting the ball,and returning to the position with the swing.（3）Information collection and data analysis: 3D high-speed photography（100Hz）and synchronous EMG test（2000Hz）were used for information collection,and SIMIMOTION kinematic analysis software and EMG analysis software MEGAWIN were used for analysis,and a total of 17 points of the human body were analyzed.Data analysis,analysis of s EMG amplitude change and contribution rate and other data,after statistical sorting out kinematic indicators such as time,joint angle,joint speed,center of gravity height and surface EMG indicators,the EMG indicators include each Stages are tested muscle RMS EMG and muscle contribution.3.Mathematical statistics method: Finally,use Excel table statistics and SPSS26 to conduct independent sample T test on the data.Research results:（1）During the batting process,the second-level group’s time in the start-up stage,the time in the lead-in stage,the time in the swing and hit,and the time in the follow-up swing were significantly shorter than those of the special students（p < 0.05）.（2）The RMS discharge of the right rectus femoris,right biceps femoris,left rectus femoris and left biceps femoris of the second-level athletes in the start-up stage was significantly greater than that of the special students（p<0.05）;At the end time,the left knee angle,right knee angle and right wrist angle of the second-level group were significantly larger than those of the special group;the combined speed of the left ankle,right ankle,left knee,and left hip of the second-level athletes was significantly higher than that of the special students（p<0.05）.).（3）The RMS discharges of the right rectus femoris,left biceps femoris and left gastrocnemius muscle of the second-level athletes were significantly greater than those of the special group during the moving positioning stage;Significantly higher than that of special students（p<0.05）;at the end of moving positioning,the combined velocity of left ankle,right ankle,left hip and right hip were significantly greater than those of special students（p<0.05）,（4）The RMS discharge of the right brachioradialis muscle and left biceps femoris of the second-level athletes during the lead-in stage was significantly greater than that of the special students（p<0.05）.The angles were higher than those of special students（p<0.05）.（5）The RMS of the middle deltoid and the right rectus femoris of the second-level athletes in the swinging and hitting stage were significantly greater than those of the special group（p<0.05）,and the RMS discharge height of the right biceps femoris in the second-level group was significantly greater than that of the special group（p<0.05）.Special group（p < 0.01）;the right hip angle and right shoulder angle of the second-level athletes were significantly greater than those of the special students（p < 0.05）,and the combined speed of the right knee and the right wrist of the second-level athletes were significantly greater than those of the special students（p < 0.05）.（6）The RMS discharge of the right brachioradialis muscle and the left gastrocnemius muscle of the second-level athletes in the follow-up return stage was significantly greater than that of the special students（p < 0.05）,and the height of the middle deltoid of the right deltoid wassignificantly greater than that of the special students（p < 0.05）.<0.01),at the end of the swing,the right knee angle,left hip angle and right hip angle of the second-level athletes were significantly larger than those of the special students（p < 0.05）,and the right wrist angle of the second group was significantly smaller than that of the special students（p< 0.05）.Analysis conclusion:（1）Excessive knee angle at the end of the start is not conducive to lower limb muscle contraction and elastic potential energy storage.The joint velocity of the left ankle,right ankle,left knee,and left hip is derived from the effective resultant force formed between the joints.（2）The more the left hip angle increases in the moving positioning stage,the more force the left biceps femoris and the left gastrocnemius are exerted,the more sufficient the pushing and stretching force,and the stronger the momentum transmission ability;the more the right elbow angle increases,the more Conducive to grabbing high-click balls,with higher consistency of action and stronger concealment.The greater the joint velocity of the left and right ankle joints and the left and right hip joints,the more helpful the body to transfer momentum from bottom to top.（3）Balanced distribution and utilization of active and passive muscles can improve the effective conversion rate of muscle energy.（4）Ankle-knee-hip-shoulder-elbow-wrist showed an increasing speed in the swinging and hitting stage,which was in line with the principle of whiplash.The right shoulder angle shows an increasing trend,and a large shoulder angle is conducive to reducing the swing distance.The less the hip angle is reduced,the easier it is to control the center of gravity of the body,which is conducive to buffering;the greater the force of the right rectus femoris and the right biceps femoris,the more conducive to the stable support of the lower limbs and the transmission of the power chain.（5）The smaller the right wrist angle at the end of the swing,the better the unloading buffering effect;the larger the right knee and right hip angles are,which is beneficial to the buffering and braking after the front foot lands.（6）From the time parameters of each stage,the effective use of time is also a key factor to improve the quality of the shot;from the point of view of the center of gravity trend,a high center of gravity is more conducive to moving and hitting the ball than a low center of gravity during the entire hitting process. |
