Analysis On The Kinematics Characteristics Of Shandong Elite Male 200m Athletes’ Running Techniques On The Way To The Curve

The men’s 200 meter dash plays a very important role in track and field events in our country,and gradually has strong competitive power in the international arena.Curve running technique plays an extremely important role in the performance of 200-meter sprint,especially the mid-curve running section to the acceleration section at the bottom corner,which lays the speed foundation for the last 70 meters or so of straight running.In this paper,the kinematics analysis of the technical movements in the "mid-run section[45m-85m]" of 200-meter sprinters in Shandong Province is carried out,which is helpful for athletes to better understand the mid-run technology of the curve,and can provide theoretical data for coaches,as well as kinematic indexes and scientific basis for mid-run training of the curve,so as to improve the scientific and data-based training.This paper adopts the methods of literature,expert interview,three-dimensional video analysis,mathematical statistics and so on.The video was shot by a high-speed camera and analyzed to obtain the kinemical data of the mid-run technology of the first,third and fifth curves.Microsoft Excel2021 and SPSS26.0 were used for graphic drawing and variance analysis of the collected data to ensure the accuracy and objectivity of the research results.Research results:1.Step length and step frequency: the step length index of 4 200-meter sprinters in Shandong Province is more prominent,which is greater than the average 1.2 of excellent athletes,belonging to the technical characteristics of step length;However,except for Xie** which reached 8.086,the maximum average of the other three athletes’ stride frequency index was about 0.216 lower than that of the elite athletes,which showed great potential in stride frequency index.2.Moving speed of the center of gravity: the moving speed of the center of gravity in the running stage of the curve increases with the increase of the radius of the curve;The maximum average moving speed of the center of gravity in different passes is only9.323m/s,while the average moving speed of the world elite athletes is 9.783m/s,and the difference between the two is obvious.3.Inward tilt Angle of the body: In a multiple step in the running stage of the curve,the inward tilt Angle of the body in each stage presents a fluctuating trend,gradually decreasing from left support to airborne support,and then gradually increasing from airborne support to right support.With the increase of the radius of the bend,the change range of the inward tilt Angle of the body increases,showing an unstable increasing property.4.Support and airborne time: The ratio of one step in the air support time in the running stage of the curve is similar to the data of elite athletes in the United States,and shows a trend of decreasing with the increase of the radius of the curve,which is in line with the main development trend of modern sprinting single step technology.5.Extension velocity of both sides of the hip: the average extension velocity of the left hip is lower than the average extension velocity of the right hip in mid-run stages of different curves,and with the increase of curve radius,the extension velocity of both left and right hips shows a gradual increase trend.6.At the end of the push back:The left arm Angle swing range is basically between43.9°-44.5°,and the right arm Angle swing range is between 47.5°-48.6°.The right arm swing range is always greater than the left arm swing range,and with the increase of the bend radius,the difference of the left and right arm swing range shows a gradual increase.But the amplitude of the four athletes in Shandong Province is smaller than that of the outstanding athletes at home and abroad.Compared with elite athletes at home and abroad,the included Angle between the thighs is larger.Although it is conducive to the increase of stride length,it also restricts the acceleration of stride frequency of athletes.Uncoordinated stride length and stride frequency will bring adverse effects on the improvement of athletic performance.7.Ankle and knee angles of the supporting leg and the swinging leg in the supporting stage: the lower limb joints show technical characteristics such as smaller knee Angle of the supporting leg,larger knee Angle of the swinging leg and larger Angle of the ankle joint at the moment of landing buffering;At the moment of vertical support,the ankle and knee joints of swing leg show the technical characteristics of too large Angle.At the end of the rear push,the knee Angle of the supporting leg and the swinging leg is reasonable,but the Angle of the ankle joint is too large,resulting in the adverse effect of increasing the vertical component and decreasing the horizontal component in the rear push.Conclusions:1.The four athletes in Shandong Province had excellent stride length index and great potential stride frequency index during the course of running in the curve.From the first course to the fifth course,the inward tilt Angle of the body and the movement speed of the center of gravity gradually increased,but the average speed of the center of gravity movement of the four competitors was inferior to that of the elite athletes,which was the main reason affecting the improvement of athletic performance.2.At the moment at the end of the push off after running in the curve,from the first to the fifth course,the swing amplitude of the left arm is always less than that of the right arm,and the swing amplitude of the left and right arm is less than that of the elite athletes,which weakens the driving effect of the swing arm on the torso,which is related to the weak upper body strength and poor flexibility and flexibility of the shoulder joint.The larger value of the Angle between the two thighs is conducive to the improvement of step length,but also restricts the acceleration of step frequency.3.The Angle of ankle and knee in the support stage determines the effect of landing cushioning and pushing force of lower limbs.Smaller knee Angle and larger ankle Angle at the moment of landing,larger ankle and knee Angle at the moment of vertical support,and larger ankle Angle at the moment of the end of back push are the ankle and knee Angle problems that significantly affect the push force of the four athletes in Shandong Province.