Study On Lower Limb Kinematics And Semg Characteristics Of Spike Take-off Of High-level Volleyball Players In Different Positions

Research objectives: Reveal the action structure characteristics and muscle working principle and mechanism of different special volleyball players in the process of spiking and taking off,accurately grasp the differences between the main attack,secondary attack and second pass special spiking and taking off of High-level Men’s volleyball players,and provide enlightening ideas and technical parameters for establishing correct special technical specifications,scientifically arranging special physical training and even special physical training.Research methods: Taking the spiking and jumping of High-level Men’s volleyball players in Yanshan University as the research object,the spiking and jumping movements of their respective positions are monitored by Quali Sys infrared motion capture system and Delsys surface electromyography system,from which the relevant data of kinematics and surface electromyography are obtained,and the obtained data are compared and analyzed in combination with literature and mathematical statistics to reveal the differences between their technical links,To clarify its principle and mechanism.Research results:(1)In the buffering stage of spiking take-off,the distance between the right foot and the projection point of the center of gravity is 0.01 M for the main attack position,-0.21 m for the secondary attack position and 0.27 m for the response position when the three special positions land together.There is a very significant difference among the three special positions(P <.01).Among them,the right foot of the main attack position and the response position is behind the hip joint,and the right foot of the secondary attack position is in front of the hip joint.The parallel step distance of the three special positions had a very significant difference(P <.01).The distance between the feet was respectively 0.84 M,0.56 m and0.26 M.(2)The maximum buffering angle of the right knee joint of the three positions is as follows: secondary attack,main attack and response position,among which there is significant difference between secondary attack and response position(P <.05).The maximum buffering angle of the right knee joint of the secondary attack special position is106.80 °,the difference between the right knee joint and the left knee joint is 21.53 °,the maximum buffering angle of the right knee joint of the main attack special position is 93.93 °,the difference between the right knee joint and the left knee joint is 43.07 °,the maximum buffering angle of the right knee joint of the receiving special position is 88.15 °,and the difference between the right knee joint and the left knee joint is 54.5 °.(3)The difference of EMG contribution rate of left and right lower limb muscle group integration in the three position buffer stage.The activation degree of the right muscle group of the main attack and response athletes was higher than that of the left.The contribution of the right muscle group was generally higher than that of the left,and the contribution of the left semitendinosus and lateral head of gastrocnemius was higher than that of the right.(4)There was a difference in the contribution rate of electromyography between the left and right lower limb muscle groups in the pedaling and stretching stage of the three special positions.The activation degree of the left muscle group is generally higher than that of the right muscle group,and the activation degree of the right semitendinosus muscle is higher than that of the left.The contribution of the left rectus femoris muscle,lateral femoral muscle,semitendinosus muscle,lateral head of gastrocnemius muscle and anterior tibial muscle is greater than that of the right,and the contribution of the right gluteus maximus muscle and medial femoral muscle is greater than that of the left.The contribution of the left muscle group is generally greater than that of the right,and the contribution of the lateral head of the right semitendinosus and gastrocnemius is greater than that of the left.Research conclusion:(1)In the buffering stage of the spike take-off,the angle difference between the left and right knee joints of the main attack and the receiving position is large,which is mainly borne by the inertia of the right leg and the weight of the human body;The angle difference between the left and right knee joints of the secondary attack position is small,and the stress on both legs is relatively balanced.In the special strength training,we should pay attention to the stress characteristics of different athletes’ legs and reasonably construct the movement mode.(2)The contribution of the right leg muscle group is generally greater than that of the left leg muscle group in the buffering stage,and the contribution of the left leg muscle group is generally greater than that of the right leg muscle group in the pedaling and stretching stage.The characteristics of unilateral support,center of gravity conversion and unbalanced force of the main attack and response athletes are more obvious.The forces on the two legs of the secondary attack athletes are relatively balanced,and the degree of unilateral support force is relatively small.(3)The medial femoral muscle and lateral femoral muscle with three specific positions contributed more to each stage,and the rectus femoris and anterior tibialis muscle also played a more prominent role in the buffer stage;In the pedaling and stretching stage,the main attack is on the lateral head of the gastrocnemius muscle,the secondary attack is on the rectus femoris muscle,and the semitendinosus muscle and the lateral head of the gastrocnemius muscle are connected to the specific position.Their contribution is also at a high level,playing the same important role as the medial and lateral femoris muscles,and they are the main muscle groups to complete the pedaling and stretching movement.