Research On Biomechanical Characteristics Of Male Tennis Players' Step-by-step Technique

Research purpose: Foot technology plays an important role in tennis,and it is one of the key technologies for athletes to win the game.The step is a very important technical action in the tennis step.In tennis,the role of the leg is to convey the athlete’s body to a positive signal,and then for the entire batting process of smooth and stability to do the next bedding.Athletes in the serve,through the legs to keep the body of the "activity",so that the body center of gravity to reduce the legs bent reserve power for the better fight back the other serve to prepare.Through the study of a large number of domestic and foreign literature can be known at home and abroad at home and abroad scientific research workers on the tennis step in the leg of the step technology only to stay in its definition,classification and training methods of the article more,but not The researchers also use the three-dimensional analysis method,the three-dimensional force measurement system and the surface electromyography test to provide a certain theoretical reference for the tennis coaches and athletes.Methods:Three machine synchronization measurement method: The experiment uses high-speed camera,three-dimensional power station and surface electromyography tester three kinds of equipment for men’s tennis players to send the ball sub-step technology to synchronize the measurement.1)three-dimensional video analysis method,the experiment using two high-speed camera,shooting frequency 50 frames / sec.From their different angles to shoot subjects in the laboratory to do the ball of the legs of the step action.The acquired video is analyzed using the 3D-SignalTec analysis system to obtain the kinematic parameters required for the study.2)Three-dimensional force measurement system test,the experiment uses the Swiss Kistler research and development of the three-dimensional force measurement system,the athletes to do the bottom line of the ball sub-step foot technology steps to test the whole process.The Using Bioware matching analysis software,and then deal with and analyze the experimental data collected by the original,in order to obtain the required three-dimensional force measurement parameters.3)surface electromyography test,the experiment selected NoraxonTelemyo2400DTS08 wireless surface electromyography instrument,the choice of the subject’s lower limb main force muscle group,respectively,lateral femoral muscle,rectus femoris,tibialis anterior muscle and gastrocnemius muscle a total of four lower limbs Epidermal muscle,using the Megawin software to obtain the athletes to do the leg of the step-up action of the EMG data analysis.The conclusion of the study: 1)Kinematic conclusion,the average height of the body’s center of gravity is 0.85 m,the angle of the knee ankle joint is lower than that of the knee at the lowest time,which indicates that the body’s center of gravity is reduced to a certain extent,Keep the body dynamic and prepare for the batting.Hip angle changes are not obvious,to maintain the upper body forward is conducive to hit the ball start.The angle of hip and ankle joint in the pedicle extension stage is increasing,which shows that the working mode and the amplitude of the extensor muscle of the hip and ankle joint will be different from the direction of the ball and the line.Athletes in the vacated stage,the hip angle was reduced trend,knee ankle angle was first reduced after the trend,which is an instinctive response to the human body,due to the role of muscle in the central nervous system under the control of the impact of the muscles will face Force in advance of the relevant muscle groups to make stress preparedness caused.The subject to do the ball and legs of the footsteps of the technical action when the shoulder at different times the angle of the angle of view,in the knees squatting to the lowest moment because the athlete’s right foot than the left foot forward.Ankle angle is less than the knee angle,is conducive to support the upper body to maintain a smooth.Two shoulder angle for the right shoulder slightly ahead of the left shoulder angle.Feet landing time,before and after and around the foot pitch changes significantly.This shows that the athlete is ready to start to vacate the body center of gravity to the highest point should be left and right foot before and after the distance,left and right spacing to adjust the size of the appropriate hitting the ball.2)kinetic conclusions,the athletes in the process of doing the ball after the step of the action of Fx and Fy force value change is not obvious in the Fz force values have significant changes,indicating that the athletes in the left and right direction to maintain a relatively stable body,Through the extension of the ground to obtain the vertical force,increase the punch before the explosive force.By comparing the changes in the values of Fx,Fy and Fz,the athlete can obtain the larger ground reaction force and increase the force value in the vertical direction by pushing the lower limb joint.3)the surface of the EMG conclusion,the athletes in the ball to take the ball step step technical action step extension stage,four muscles are involved in the work.The activity of the gastrocnemius muscle in the four muscles was the largest,and the integral electromyography activity of the lateral femoral muscle was weaker than that of the rectus muscle,the gastrocnemius muscle and the tibialis anterior muscle,which indicated that the athlete had increased the knee ankle movement in the pedal stage than the hip and knee.Athletes in the ball to take the ball step step technical action vacated stage,four muscles are also involved in the work.Four muscles in the gastrocnemius muscle activity intensity,followed by the tibialis anterior muscle,lateral femoral muscle myoelectric activity than the rectus femoris,gastrocnemius and tibialis anterior muscle weak.The mean integral electromyography of the femoral and femoral rectus of the vacuolar phase was lower than that of the pedicel stage,and the average integral electromyography of the gastrocnemius and tibialis anterior muscle in the vacated phase increased,indicating that the fatigue of the gastrocnemius muscle was likely to occur.