Kinematics Analysis Of 1080 Degrees Movement Of Man’s Floor Exercise In The Back Of The Body

Research purposes: By using APAS three-dimensional motion analysis system,the kinematics analysis of 1080 degree back flip movement of male floor gymnasts was carried out,and the changes of various motion parameters(shoulder joint angle,hip joint angle,knee joint angle,time and angular velocity)of Shanxi elite gymnasts Xiangxudong and Du Yuliang in the course of completing the movement were compared and analyzed.It not only provides a scientific basis for athletes to analyze and diagnose the technical movements,but also provides a scientific basis for Shanxi gymnastics team to obtain excellent results in the preparatory competition.Research methods:In the experiment,Xiangxudong and Du Yuliang,the elite gymnasts of Shanxi Province,were selected as subjects.Xiangxudong won the second place in men’s floor exercises in the 2016 championship and Du Yuliang won the first place in men’s floor exercises in the 2018 National Youth Championship.Two high-speed video cameras were used to shoot the 1080 degree backward flip of the Back Handspring straight gymnastics.Find out the relevant literature about the kinematics analysis of floor exercises skills,and provide theoretical basis for the further study;Expert interview method,interviewed teachers,students of sports biomechanics specialty and coaches,referees and gymnastics teachers of Shanxi gymnastics team,which provided accurate reference for the experimental operation and the determination of the time phase and parameters of technical movement analysis in this paper.Video analysis method,using APAS three-dimensional motion analysis system to analyze the motion video;mathematical statistics method,using EXCEL to analyze the motion data routinely,combining with the theory of motion technology to analyze and sort out the relevant results.Research result:(1)Scorpion stage:When starting,the shoulder,hip and knee angles of Xiangxudong are larger.Du Yuliang did not stretch his shoulder and hip enough at the beginning of his hand,while Xiangxudong had a larger shoulder angle than Du Yuliang when pushing his hand.Du Yuliang’s hip angle is bigger than Xiangxudong’s;when he tightens his legs,the trajectory of their center of gravity first rises and then decreases.(2)After the hand-turning stage: when foot touches the ground,the angle of shoulder,hip and knee joint of Xiangxudong is larger than that of Du Yuliang;when kicking back,the angle of shoulder joint of Xiangxudong is larger,the angle of hip joint is smaller,and the angle of knee joint is smaller;when the first flight,the length of time of both men is 0.14 s,the angle of shoulder joint and knee joint of Xiangxudong is larger,and the angle of hip joint of Du Yuliang is at the initial stage angle.The angle of shoulder and hip joints is larger and the angle of knee joint is smaller when the hand supports;the angle of hip joint is smaller when pushing off the ground;the length of two people is 0.10 s when the second flight time,the angle of hip joint shows a downward trend;the angle of shoulder joint is smaller when the foot lands,and the angle of hip joint is larger.(3)Straight body back-flip body 1080 ° stage: Du Yuliang’s take-off angle is reasonable,the take-off angle towards Xudong is larger,the take-off time is longer,the shoulder joint and hip joint of the two people show the characteristics of lower left than right,the turning time towards Xudong is shorter and the turning angular speed is faster when the air somersault is between 0 degree and 360 degree,ranging from 360 degree to 720 degree.The turning time to Xudong is shorter and the turning speed is faster,but the right arm is not tightly held.At 720 degrees to 1080 degrees,the turning speed and angular speed to Xudong are larger.At the highest point,Xiangxudong’s aerial height is higher;at the landing stage,Xiangxudong’s left shoulder joint is smaller,his two hip joints are larger and his knees are larger.Research conclusions:(1)Scorpion stage: Xiangxudong shoulder,hip,knee joint angle is more reasonable,in the start,push hand phase performance is better,the characteristics of push hand strength,Du Yuliang’s kinetic energy is smaller,overall,Xiangxudong is better,and Du Yuliang in the start,push hand there are certain deficiencies.(2)After the hand-turning stage: Back-handspring is an important link link of the movement,it should be directed,action stretching,rhythm can ensure success.Shoulder,hip and knee angle play an important role in the completion of follow-up movements.Xiangxudong’s movement is characterized by strong rhythm.Du Yuliang’s movement is characterized by inadequate stretching.As a whole,Xiangxudong is more excellent.Shoulder,hip and knee joint angles are suitable for the development of subsequent difficult movements.(3)Straight body back-flip body 1080 ° stage: Xiangxudong’s take-off time is reasonable,which is characterized by sufficient kinetic energy.Du Yuliang’s take-off angle and the action of the overturn body are excellent,which make the human body complete the action better on the oblique top.Its characteristic is that the turning radius is small and the unnecessary loss of kinetic energy is avoided as far as possible.On the whole,Du Yuliang is better.