Research On The Biomechanical Differences Of Backhand Attacking Straight And Oblique Spinning Techniques In Table Tennis

Aim:The aim of this paper is to reveal the technical action law of table tennis backhand stroke by using kinematics and dynamics analysis,and to find out the technical difference between hitting straight and oblique line of ping-pong backhand stroke.The results will provide a theoretical basis for the teaching and training of table tennis coaches,athletes and table tennis enthusiasts.Methods:Eight high-level female table tennis players from colleges and universities were selected as subjects,and the backhand hitting straight line and oblique overturning ball technique were completed respectively.Ten Qualisys infrared motion capture lenses with the sampling frequency of 200Hz were used to simultaneously collect the kinematic data of the hitting technique of the subjects.At the same time,the mechanical data were collected synchronously by two three-dimensional Kistler dynamometer,the frequency of which was 1000Hz.The human body model was constructed by Visual3D,and the angle,angular velocity and torque were analyzed.The moment values obtained from the software developed by ourselves were standardized by the height and weight of the subjects(dimensionless).SPSS 19.0 software was used for paired sample T test,and the level of significance was set to ? = 0.05.Using Origin2017 to complete drawing.Results:1.There was a significant difference in the wrist flexion angle between the two batting lines,including a oblique line of 24 and a straight line of 68,P=0.036.The angular velocity of flexion and extension of oblique ball wrist joint is-648,while that of straight line ball wrist joint is 248,P= 0.012.In swing stroke stage,the wrist abduction and flexor moment are different,and the straight line is larger than the oblique line.2.In the joint of upper limb,the velocity of shoulder flexion and adductive angle were significantly different.The angular velocity of flexion was 190 in oblique line,248 in straight line,P= 0.036.The angle velocity oblique line is 76,straight lineis 140.P=0.012.3.The flexion angle of the right knee joint is-29.8 straight line-37.2,P= 0.012 at the stroke time.In the swing stage,the bending moment of the right knee is obviously larger than that of the oblique line.The angle of right ankle dorsiflexion was 82 straight line 88,P= 0.012;left ankle joint dorsiflexion oblique line was 81 straight line 88,P =0.036.Conclusion:1.In the course of swing stroke,the range of flexion and extension of the wrist joint is larger and the swing speed is faster when hitting the oblique line,on the contrary,the wrist of the straight line ball is relatively fixed and keeps the flexion angle.The main torque of wrist joint is flexor muscle and abductor muscle,and the force is greater than that of oblique ball.2.When hitting the ball to straight line,the angular velocity of shoulder joint flexion and extension,adduction,elbow joint flexion and extension is larger than that of slant line.When hitting the ball to the oblique line,the angular velocity of the shoulder and elbow joint rotation is larger than the straight line.When the backhand hits the ball to the oblique line,the angular velocity of each joint of the upper limb is higher,and the speed of flexion and extension of each joint is more dependent on the straight line.3.The flexion angle of the left knee is smaller than that of the right knee,showing the body posture of the right knee bending and the left knee stretching.When hitting the oblique line,the flexion angle of the left and right knees is more consistent.