Kinematics And Electromyography Analysis Of Backhand Loop In Table Tennis

The backhand loop technique of four second-level table tennis players was tested by high-speed camera and surface emg equipment.By analyzing the changes of joint Angle and speed,time,displacement and speed of swing,the changes of electromyography,integral electromyogram and the changes of work and load of each major muscle group of the human body in the backhand loop.This paper aims to explore the characteristics and rules of backhand loop and provide a theoretical basis for the training and teaching of backhand loop.Methods: this paper studied the backhand loop technique of table tennis players by means of literature review,experiment,expert interview and mathematical statistics,and obtained the relevant parameters of the whole movement cycle.Research results:1.In the backhand loop,the lead time accounts for 37.86%,the swing time accounts for 24.85% and the return time accounts for 36.95%.The curve of racquet speed increases sharply and then decreases rapidly during the swing.2.In the swing and hit stage,the power of upper limbs conforms to the whipping principle,the maximum speed of each joint of the body appears from early to late in the order of knee joint,hip joint,shoulder joint,elbow joint and wrist joint,and the maximum speed of the racket appears at the latest.3.In the backhand loop ball movement,the degree of shoulder joint adduction is obvious,the degree of elbow joint flexion and extension is small,the rapid flexion and extension of wrist joint mainly occurs before the hitting time,the Angle of lower limb joint increases significantly in the hitting stage,and the Angle of hip joint is greater than that of knee joint.4.During the swing,the big arm drives the forearm forward to meet the ball.The main power link is elbow extension and wrist swing,followed by the lower limb kick and turn,and the waist and abdomen force is relatively small.5.In the electromyographic study of backhand arcus technique,the integral emgvalues of the middle band of deltoid and biceps of humerus were larger in the whole course of the action,followed by quadriceps,gastrocnemius and pectoralis major,and the integral emg values of the external oblique,erector ridge and latissimus dorsi were smaller.The contribution rate of the shoulder and arm was the highest,followed by the muscle group of the lower limbs,and the contribution rate of the core muscle group was relatively less.