Comparative Analysis Of Surface Electromyography Between Backhand Forward Arc Ball And Round Arc Ball Of Table Tennis

Research purpose: Table tennis arc ball technology is an important reference for measuring the level of a table tennis player,and backhand arc ball technology is an important offensive and defensive key technology.In this study,eight muscles of table tennis players performed backhand forward arcs and extra rounds to test their muscle surface electromyography.Analyze the identity and difference of the EMG signal parameters between the two.Provide more scientific theoretical basis for table tennis youth enlightenment,table tennis players and coaches.Research methods: Seven Guangdong national first-level athletes and one national second-level athlete were taken as test objects.During the formal test,eight athletes took turns to make backhand forward and add turns,and used the Delsus Trigno TMlab wireless from the United States.Surface electromyography test system and related accessories,collect subject EMG signal parameters during prescribed movements,analyze activation,inactivation time,duration of muscle strength,root mean square amplitude and integral electromyography between two movements value.Main results of the study:(1)In the swinging and hitting stage: the sequence of muscle activation of the two movements is roughly the same,the medial femoral muscles of the leg muscles,the anterior tibial muscles and the deltoid muscles of the upper limbs are activated first;It is the anterior tibial muscle,medial femoral muscle and gastrocnemius muscle of the leg muscles;from the duration of the entire muscle,the rotation of the arc ball is longer than that of the forward lap ball,and the rotation of the arc ball is the thigh muscle.The duration is relatively long;from the perspective of muscle contribution rate,the upper limb contribution rate of the forward arc circle ball is 50.66%,and the trunk is 26.38%.The proportion of the two parts is relatively large.,The proportion of the two parts is relatively large;from the root mean square amplitude,the discharge of the deltoid posterior bundle and the upper part of the trapezius muscle are obvious in the two actions,and the overall discharge of the rotating arc ball is lighter.(2)In the swing phase: from the perspective of muscle contribution rate,bothmovements have a relatively large contribution rate of the upper limb and trunk muscles,61%of the upper limb of the forward ball,25.91% of the trunk,and 64.51% of the upper limb of the arc ball.The torso is 19.89%;from the root mean square amplitude,the three muscles of the forward arc loop ulnar side flexor,upper trapezius,and middle trapezius muscle have obvious activity,and the center of gravity changes little,and the arc ulnar side wrist The posterior bundle discharge of flexor and deltoid muscles is obvious.The main research conclusions:(1)Judging from the activation time of the muscles,the activation sequence of the muscles in the two technical movements is basically the same in the swinging and hitting phase.Basically,the leg muscles are activated first.(2)From the point of view of muscle deactivation time,during the swinging and hitting phases of the two technical movements,the lower extremity muscle groups generally show relatively early inactivation,while the inactivation time of the trunk and upper extremity muscle groups differs.(3)Judging from the duration of the muscles,there is a significant difference in the duration of the muscles between the two technical movements during the swinging and striking phase.The continuous discharge time of the rotating arc ball will be longer than that of the forward arc circle ball,and the continuous discharge The longest muscles are the deltoid midbeam.(4)From the point of view of the muscle’s integral EMG value,the muscles with larger integral EMG values during the swing phase of the two technical movements include the posterior deltoid muscle,the upper trapezius muscle,and the anterior tibial muscle(left).In terms of the respective contribution rates of the lower limbs and the torso,the forward lap ball movement requires more coordination of the upper limbs and torso;the addition of the lap ball movement requires more coordination of the legs and waist hips.In the follow-up phase,the deltoid posterior bundle and the ulnar carpal flexor muscle are the main force-building muscles of the two technical movements.Overall,the two technical movements have significant differences in the upper limb and trunk muscle groups.(5)Judging from the root mean square amplitude of the muscles,the average discharge level of these muscles in the mid deltoid,posterior deltoid,ulnar carpal flexor,and uppertrapezius muscles during the swing phase of the forward lap ball higher.In the follow-up phase,the relatively high discharge levels of the two technical actions are the ulnar carpal flexor and upper trapezius,and the relatively smaller ones are the gastrocnemius(right)and medial femoral muscle(left),indicating that the main follow-up phase It is the upper limbs and torso,and the lower limbs are more supporting and maintaining balance.