The Biomechanical Analysis Of Excellent Male Shake-hand Grip Table Tennis Athlete's Backhand Underspin Pull Ball Technical Action

Table tennis backhand downward spin pull technology is the main technology in table tennis,but also the basic technology of backhand downward spin.Continuous improvement and improvement of backhand downward spin pull technology is the direction of every professional table tennis player and amateur table tennis fans.Increasing the research on the technique of backhand downward spin can give the correct theoretical guidance to table tennis fans and professional players.In this paper,15 men's table tennis players with the right hand holding racket at the first level or above of the national sports level are taken as the research objects.By using electromyography analysis technology and three-dimensional motion capture technology,the technical movements of table tennis backhand downward rotation and pull ball are analyzed.From the perspective of joint,swing speed,the time,time sequence and work of each muscle,the technical movements of backhand downward rotation and pull ball are revealed The characteristics of biomechanics.On the one hand,the data can guide the practice scientifically and improve the skill level of table tennis players in all stages.On the other hand,it can enrich the biomechanical research content of table tennis backhand downward spin and pull technology in theory,and provide scientific reference for other sports biomechanical research.After sorting out the data,the final conclusions are as follows:(1)In the shake-hand grip backhand downward rotation and pull ball movement,the best angles of each joint are: elbow joint 95.36 degrees,right knee joint 114.37 degrees,left knee joint 133.9 degrees,right hip joint 109.08 degrees,left hip joint 114.2 degrees,right ankle joint 77.75 degrees,left ankle joint 98.25 degrees.At the moment of maximum leading stroke,the bending angle of each joint on the right side of the body should be greater than that on the left side of the body,so that the degree of leading stroke is more sufficient,which is conducive to the accumulation of force before swinging and hitting the ball.(2)In the moment of swing,the best angles of each joint are: 135.05 degrees of elbow joint,116.33 degrees of right knee joint,133.74 degrees of left knee joint,127.63 degrees of right hip joint,133.98 degrees of left hip joint,81.22 degrees of right ankle joint and 92.24 degrees of left ankle joint.In the moment of swinging and hitting,the bending angle of each joint on the right side of the body is slightly larger than that on the left side of the body.However,compared with the maximum shooting moment,the difference between the bending angle of each joint on the left and right side of the body at the moment of hitting should be reduced.With the help of the body,the elbow joint gradually extends and forces forward to the right.(3)At the end of the wave,the reasonable angles of each joint were 124.89 degrees for elbow joint,128.81 degrees for right knee joint,137.03 degrees for left knee joint,138.12 degrees for right hip joint,139.4 degrees for left hip joint,88.26 degrees for right ankle joint and 93.13 degrees for left ankle joint.At the moment of the end of the swing,the body's joint angles should reduce the degree of bending,and make the left and right joint angles tend to be the same,so that the body will stretch more after the end of the stroke.(4)In terms of root mean square amplitude and integral EMG value,the right pectoralis major,right biceps brachii and right trapezius muscles have the largest discharge,the highest contribution value and the highest average amplitude,indicating that these muscles play the largest role.(5)In terms of the time sequence of muscle discharge,the gastrocnemius,biceps femoris and rectus femoris of the left leg muscle group are the first to discharge the force,and the overall power sequence shows the conduction effect from the lower limb to the upper limb.In terms of the duration of muscle discharge,the Longarm muscle group and back muscle group have the longest duration,and the leg muscle group have the shortest duration,which indicates that the duration of arm and back force should be longer than that of leg force in the process of backhand downward spin and pull.