Three-dimensional Kinematics Characteristics Of The Take-off Technique Of Some Male Juvenile High Jumpers In Beijing, Tianjin And Hebei

The high jump is a kind of complicated multi-axis rotating events.Chinese athletes have achieved good results in many world competitions.Young athletes are the core strength in the future competition,and the take-off of high jump is the technical core of high jump.Therefore,this paper chooses the best jump technique of athletes in the Beijing,tianjin and hebei indoor invitational competition as the research object of this experiment.This paper divides the take-off movement into three moments and two stages,analyzes the kinematic parameters of the three moments and two stages,finds out the existing problems,puts forward reasonable Suggestions,and improves the athletes' skills to improve their performance.Through analysis,the following conclusions are drawn:1.At the moment of take-off and landing,beijing-tianjin-hebei athletes can actively send the hip and swing the ankle to give full play to the role of pushing and stretching,but there is a phenomenon of excessive knee bending at the moment of take-off.The more fully the athlete extended the swing leg of the ankle joint,the smaller the twist Angle of the shoulder and hip,the better the performance of the athlete.At this moment,the horizontal speed of the athlete's jumping leg plays an important role.The athlete's performance increases with the increase of the vertical and horizontal speed of the knee joint,the horizontal speed of the ankle joint and the center of gravity speed of the thigh.2.At the moment of maximum buffering,the athletes perform reasonably in the knee joint of the jumping leg,the knee joint Angle can be within a reasonable range,and the athletes can actively swing their legs forward.At the moment of maximum cushioning,some athletes showed that the right hip rotated forward too much and the right shoulder rotated forward not enough.At this moment,the greater the knee Angle of the swing leg,the worse the performance of the athletes.The swing of the swinging leg plays a major role,especially the knee and thigh center of gravity swing can promote the increase of athletes performance.3.At the moment of off-ground buffering,8 athletes swung their legs and sideshoulders and hips to twist positively and fully,while some athletes did not fully stretch their hips,knees and ankles.Hu yifan,jing yijing,du jiajie body too guide rod direction and swing leg did not fold swing leg.With the decrease of the Angle of the knee joint of the swinging leg and the internal and external inclination of the trunk of the body,the athlete's performance becomes worse.The ankle joint closing speed of the swinging leg,the vertical velocity of the hip and thigh center of gravity,and the horizontal velocity of the ankle joint are significantly positively correlated with the athlete's performance.4.In the maximum buffering stage,the body of the athlete can reasonably reverse to the direction of the pole,and the swinging leg can actively swing forward to send the hip.Most athletes adopt the way of folding up the calf.However,some athletes lean back seriously,during the buffer stage,the athletes take off with a longer buffer time,swing too fast to the left and turn the right hip to the right too early.5.In the stretching stage,the athletes' speed in most parts of the body tends to increase.Most athletes can extend their hips and knees in the hip and knee joints.Most athletes have too long push and push too hard and lose the elastic potential energy.The greater the change in the vertical center of gravity,the better the performance.