Biomechanical Analysis Of Blockling Straight Net Movement In Badminton Forehand

Objective: To use modern sports biomechanical techniques to conduct kinematic and electromyography measurements of badminton players’ midfield lunging and blocking straight net movement,to analyze the kinematic characteristics and electromyography characteristics of athletes,to explore the essence of technology and technical key,to establish a scientific theory and teaching mode of training,and to establish a sound training system.Methods: In this experiment,9（male）badminton secondary athletes were tested simultaneously with surface emulsion test（2000Hz）and four high-speed cameras（100Hz）.Using the "Youth Badminton Sports Skill Level" and "Badminton Sports Level Test Guide" as stipulated in the smash and blocking straight net area,using the badminton serve machine to simulate the smash in the game,the athlete uses the technical action of lunging and blocking straight net,and selects the best batting effect in the ten strokes,and uses the German SIMI MOTION three-dimensional image analysis system to analyze the data of a total of seventeen human body marker points on the human body and the electromyography analyzer（MAGE WIN6000）to s EMG qualitative and quantitative analysis of the amplitude change,the relevant time,the body center of gravity trajectory,joint angle and other kinematic results were obtained,and the right side: radial muscle（RBR）,deltoid muscle（RLD）,rectus femoris（RRF）,biceps femoris（RBF）and left: rectus femoris（LRF）,biceps femoris（LBF）,tibias muscle（LTA）,gastrocnemius muscle（LLG）these 8 muscles at each stage RMS value and muscle activation sequence and other myoelectric indicators,The maximum voluntary isometric contraction（MVIC）of the measured muscles is measured,and the size of the RMS ratio measured by the test muscles to the RMS measured by the MVIC represents the degree of muscle activation.Statistical methods are used to organize and analyze,and the movement trend is standardized.Results:（1）From the perspective of the whole action,the T3 stage time is the shortest（0.05s）,the T4 stage is the longest time（1.11s）,and the activation sequence of each muscle is LLG-LBF-LRFLTA-RRF-RBR-RLD-RBF;The results showed that muscle activation was most pronounced in RBR（0.38）,RRF（0.41）,and LLG（0.42）.（2）The center of gravity of the starting stage shows a small and brief increase and then a sharp decline,to the lowest time the center of gravity rises,the lower limb joint angle is 125.42 ° ± 13.45 °,the right knee angle is 134.77 ° ± 10.50 °,the right ankle angle is 87.86 ° ± 15.16 ° the left hip angle is 143.68 ° ± 11.02 °,the left knee angle is 138.96 ° ± 13.65 °,the left ankle angle is 92.78 ° ±11.87 °.In the initiation stage,the lower limb muscle activity is relatively strong,and the degree of LLG activation is the highest（0.55）,followed by left and right RBF,and the lowest RLD.（3）The movement distance and movement speed of the right foot in the lunging pedaling stage are greater than those of the left foot,and the three links of shoulder,elbow and wrist at the end of the shooting have completed backward extension（right wrist joint angle: 145.17 °,right elbow joint angle: 155.32 °,shoulder joint abduction angle: 140.70 °,shoulder joint flexion angle: 74.89 °）;The center of gravity of the body gradually moves forward,rapidly to the right,and then lowers after lifting,and the center of gravity is lowered to the lowest point at the end of the stroke,reaching a large shoulder hip angle（19.88°）;At this stage,RRF and LLG activation are higher.（4）The athletes in the batting stage are in a buffer imbalance state at this time,but in general,the athletes have larger joint angles.In the batting stage,the speed of the joints of the trunk and upper limbs is small to large,which is the trunk-shoulder joint-elbow joint-wrist joint-hand-racket,and the angle of the racket surface does not change much（1.37 °）in the process of catching and blocking straight balls,and the degree of activation of RBR is the highest.（5）The left foot movement distance（0.95m）and movement speed（0.83m/s）in the swing back to the middle stage are greater than those in the pedaling and shooting stage;LLG,RBR,and RRF are highly activated.Conclusions:（1）The center of gravity of the body in the starting stage shows a downward trend to the right and downward,thereby improving the stability of the body and helping to judge the direction of the ball;The degree of force of the left gastrocnemius muscle is obvious,which creates favorable conditions for obtaining a faster rightward departure speed.（2）The rectus femoris muscle on the right side of the pedaling stage is the most obvious,and it is quickly moved to the right to the best batting position;The center of gravity of the body shows a trend of first rising and then falling,stretching out to find the batting point,and the torsion angle of the torso shows an increasing trend.（3）The batting stage takes the shortest time,and the joints on the side of the clapping hand and the speed transmission of the racket conform to the principle of whipping;The right humerus radial muscle is the most pronounced,and the arm is slightly rotated inwards,which helps to control the batting surface.（4）It takes the longest time to swing back to the middle stage,and the distance of footstep movement increases;The left gastrocnemius muscle and the right humerus radial muscle are the most pronounced,the forearm is rotated and unloaded,and the body is buffered first and then quickly returned to position,fully prepared for the next shot.