Study On Kinematic Characteristics Of 400m Athletes’ Bending And Straight Track Running Technology

Objective: the 400 m Race is one of the track and field sprint events.The 400 m Race is to run two semicircle curves with equal radius and two straight segments on the standard semicircle track and field field field.From the field composition,the400 m technology is composed of the curve running technology,the straight running technology and the mutual connection technology between the curve and the straight.The mastery and play of the curve and straight running technology will directly affect the performance of the 400 m athletes.Exploring the technical characteristics of curve and straight track running and the relationship between them and sports performance will help to better understand the technology of curve and straight track running,provide basis for targeted training and strengthen the scientific degree of practice.Methods: This study took 12 male 400 m runners as subjects,including 2 elite athletes,4 first-class athletes and 6 second-class athletes.By using the methods of literature,expert interview,test and mathematical statistics,the technical action images of the tested athletes in the two stages of curve and straight are captured by high-speed cameras and other equipment.In the later stage,the obtained kinematic images are analyzed by using the simi motion system,and then the technical characteristics,technical differences and the relationship with sports performance of athletes of different levels in the curve and straight are analyzed.The research results are as follows:1.The step length index of the master,first and second level athletes in the curve is 1.278,1.247 and 1.103;The step frequency index was 7.693,7.428 and 7.334;The moving speed of gravity center is 9.086m/s,8.799m/s and 8.451m/s;0.460 s,0.485 s and 0.515 s for one multi-step;The left hip speed was 9.132m/s,8.852m/s and8.587m/s;Right hip speed 9.294m/s,9.079m/s,8.792m/s;With the left leg as the swinging leg,the leg separation angles were 111.340 °,107.405 °,94.186 °;Taking the right leg as the swinging leg,the leg separation angles are 116.2 °,110.685 ° and98.814 °.2.In the straight track,the step length index of elite athletes,class I and class II athletes is 1.289,1.258 and 1.168;The step frequency index was 7.346,7.145 and6.737;The moving speed of gravity center is 8.905m/s,8.626m/s and 8.216m/s;0.486 s,0.530 s and 0.545 s for one multi-step;The left hip velocity was 8.929m/s,8.661m/s and 8.377m/s;The right hip speed was 8.880m/s,8.743m/s and 8.515m/s;With the left leg as the swinging leg,the leg separation angles are 106.040 °,102.050°,98.194 °;Taking the right leg as the swinging leg,the leg separation angles are104.85 °,104.535 ° and 97.50 °.3.The step length index,step frequency index,center of gravity moving speed,leg separation angle with left and right legs as swing legs of the athletes tested in curve running and straight running have different degrees of correlation with their performance.Research conclusions:1.In curve running,with the improvement of exercise level,the step length gradually increases,the step frequency gradually increases,the step length index and step frequency index gradually increase,the center of gravity movement speed gradually increases,the speed of left and right hip joints gradually increases,the included angle of two thighs gradually increases when the left and right legs are the swing legs respectively,the hip angle of the support leg gradually increases when the ground is off,and the hip angle of the swing leg gradually decreases,The angle of the ankle joint of the supporting leg gradually increases at the end of the push back,and the inclination angle of the body presents a fluctuating law.2.In straight track running,with the improvement of sports grade,the step length gradually increases,the step frequency gradually increases,the step index and step frequency index gradually increase,the center of gravity movement speed gradually increases,the speed of left and right hip joints gradually increases,the angle between the left and right arms and trunk gradually increases,the angle between the two thighs gradually increases when the left and right legs are swing legs respectively,and the hip angle of the support leg gradually increases when leaving the ground,The hip angle of the swinging leg decreases gradually,and the knee angle of the supporting leg increases gradually at the end of the back pedal,and the ankle angle of the supporting leg increases gradually.3.The athletes of different grades all showed the laws of small step length,fast step frequency,small step index,high step frequency index,short time for one repeat step,fast hip joint movement speed and large difference between the swing amplitudes of the two arms;The step frequency of the second-class athletes changes obviously in the curve and straight run,and the swing range of the lateral arm and leg of the elite athletes and the first-class athletes is more obvious in the curve run.4.To improve the 400 m performance,we should pay attention to the development of step length and step frequency,improve the moving speed of center of gravity and increase the angle between two thighs,and pay attention to the exercise of lower limb strength and upper and lower limb coordination.