The Three-dimensional Kinematic Characteristics And Influence Factor Of The Difficulty Of Attitude In Rhythmic Gymnastics

With the continuous development of rhythmic gymnastics,the quality of the completion of physical difficulty is getting higher and higher,and the difficulty of turning has always been a difficult problem that our rhythmic gymnastics needs to overcome.As a typical representative of the turning movements of rhythmic gymnastics,Attitude turning is how to maintain the best rotation posture and increase the number of turning cycles while keeping the body stable.Therefore,in order to adapt to the development trend of rhythmic gymnastics and better understand the movement of Attitude,this research uses two Nissan Panasonic NV-M D9000 cameras,using fixed point,fixed focus and fixed distance to 3 outstanding athlete of rhythmic gymnasts and 9 rhythmic gymnastics students filmed.An American ARIEL three-dimensional image analysis system was used to analyze a complete Attitude turn motion.By comparing the changes in sports biomechanics indexes of excellent rhythmic gymnastics athletes and professional gymnastics students,analyzing the technical characteristics of each link,objectively evaluating technical movements,and summing up the influencing factors,in order to provide a reference for the teaching of rhythmic gymnastics.The research conclusions are as follows:(1)Attitude turning movements are divided into three stages: pre-swing,start-up,and rotation.(2)Turning characteristics of outstanding athletes: The shoulder and hip horizontal axis rotates in the pre-swing phase,and the knee angle changes from small to large.The angular speed of the shoulder and hip joints during the start-up phase is fast.Arm to obtain a large momentum moment,and then fix the swivel posture by lifting the arms to reduce the radius of motion to reduce the moment of inertia;the limb control ability and dynamic balance ability are strong,the upper limbs,The difference between the body's center of gravity and the rotation axis is small,and the "effective rotation phase" lasts longer,accounting for 46.2% of the entire rotation movement.(3)Characteristics of rotation movement of the trainees: the amplitude of the pre-swing movement is too small,the knee joint angle changes irregularly,and the variation characteristics are quite different;the shoulder and hip angular velocities shown in the start-up molding phase are slow,and the arms are not fully opened,and The turning posture has a slow forming speed,and the upper limb movements of the "crane vertical" dance pose lack fixedness;in the rotation stage,the trainees lack the limb control ability and the "effective rotation stage" is too short,accounting for only 22.2% of the total turning movement ratio.And the difference between the upper limb movement coordinates,the body's center of gravity and the rotation axis is large.(4)Comparative analysis results: In the rotation of Attitude,the angle of rotation of the shoulders and hips of the outstanding athletes is greater than that of the trainees;the knee movement characteristics of the trainees lack regularity;when the arm is started to do circular motion,the trainees have upper limb movement The amplitude is smaller than that of excellent athletes,and the speed of "he vertical" dance is slower than that of excellent athletes.During the rotation of excellent athletes,the upper limb coordinates and body center of gravity are infinitely close to the axis of rotation.In terms of exercise time characteristics,compared with the trainees,excellent athletes' strong body control ability shows the "effective rotation phase" of absolute advantage,and Attitude turning movement is more effective.