Analysis Of The Electromyography Characteristics Of Muscle Surface Of The Youth Volleyball Player's Fourth-position Fastball Action

Volleyball as a worldwide one of the most popular ball games project in our country sports occupy an indispensable position all the time,it has a broad mass,excellent ornamental and the diversity of forms,such as special cultural charm,is a concentration of speed,endurance,explosive force,flexibility,integration movement,at the same time,the attack-defense intense,strong technical cooperation degree higher and the field has a great attraction.In a game,spiking is the most advantageous weapon in the offensive means of volleyball,is the best way to gain the initiative in the game.On the court,the spiker can not only improve the spiking effect by increasing the hitting power,but also by changing the spiking route to avoid the opponent's block,so as to find the opponent's weak area to achieve the goal of scoring.There are many factors that restrict and influence the development of volleyball,one of which is the cultivation of reserve talents for teenagers.For people aged 14-16 years old young athletes in the physical and mental and physiological function of rapid change and growth of the sensitive period,the technology of the early action learning 2 to 3 years,is also the key stage of lay a good foundation action technique,4a drop shot action is the basic technology of learning spiking action,have good foundation,to help athletes study higher spiking technique.In order to make a detailed analysis of the characteristics of players' spiking movements at position 4,athletes were selected to perform surface emg data collection for athletes at position 4 with the movements of straight line,diagonal line and small diagonal line.The different levels of the movement of athletes in spiking action in the process of muscle electromyography performance will be different,choose different levels of athletes as test object,analyzing the characteristic of the juvenile volleyball players spiking action of electromyography and with high level athletes in complete action differences that exist in the process,for the improvement of the juvenile volleyball players spiking technique action to provide the reference.In this paper,BTS FREEMG 300 32-guide wireless surface myoelectrometer was used to test 20 junior volleyball players who met the test requirements,and 10 high-level players were selected for comparative analysis with junior volleyball players.In the test,volleyballexperts check the whole process of the test and evaluate the movements.The best 3movements are selected to collect the emg data when the players do the movements of each line.The movements that do not meet the specifications are re-tested.The system is equipped with EMGSERVER software to conduct video synchronization processing on the data.After filtering and smoothing the original data,the movement data is intercepted and finally exported into excel data format.The 15 muscles of the upper and lower limbs and the trunk that form the movement chain of the volleyball spiking movement are processed.Muscle integral emg value,muscle contribution rate,activation degree and other emg indicators were calculated,and one-way anova was used for statistical analysis(the data results were expressed in the form of mean ± standard deviation).Conclusion :(1)in the movements of catching the straight line,diagonal line and small diagonal line,the main driving force muscles of the high-level athletes are the same as those of the teenagers,and the order of driving force of the muscles is from the bottom to the top.The electromyography of the muscles of the high-level athletes is the same when they hook the ball in a straight line,a diagonal line and a small diagonal line.The spiking line will not affect their muscles.In the analysis of emg index,there was no difference in emg value of muscle integral,contribution rate and activation degree.(2)in the electrical characteristics for tion stage,high level athletes at this stage,the straight line,slash,small slash ball movement muscle showed similar power laws,lower limb muscles of leading role up to close to the upper limb muscles and muscle activity is balanced,back muscles in the course of action,the abdomen and pectoralis major effect is relatively small.Young athletes button is straight line,slash,small cross-court muscle showed a larger difference,hooks and eyes straight ball and the cross action muscle activation degree contrast of deltoid muscle bundle has significant difference(P < 0.01),a ratio comparison of pectoralis major muscle,the muscle of,shaft sma has a difference(P < 0.05).It indicates that the body balance can not be well controlled,the movement proficiency is low,and the movement stability can not be well maintained in this stage.(3)in the air hitting stage,the emg features are: in the air hitting stage,the muscles of the high-level players in the straight,oblique and small oblique ball movements show similarrules of force,with the muscles of the upper limbs playing a dominant role,followed by the muscles of the lower limbs,the rectus abdominis and the erector spinae of the trunk muscles playing a more obvious role.However,there is a big difference between the main acting muscles of the upper limbs in the movements of the straight ball and the diagonal ball.The athletes focus too much on the hitting effect and ignore the coordination between the muscles,and the power transfer between the upper and lower limbs of the trunk is disjointed.(4)in the stage of buffering on the ground,the electromyography features that the high level athletes have very obvious effects on the biceps femoris and gastrocnemius of the leg muscles,indicating that buffering is very active,while the gluteus maximus and gastrocnemius have little effect.In the upper limbs and trunk group,the upper limb muscle plays a negligible role,and only the erector spine muscle plays a significant role in the trunk group.In the comparison of the three routes,the leg muscles were the main functional muscles of the young athletes,but there was a big difference.The poor movement stability resulted in the failure to finish the active buffering when landing,and the primary and secondary relationship between the upper limbs and trunk muscles was not obvious,resulting in the imbalance of exertion.