Research On The Kinematics Evaluation Indexes Of Snatch Technique Of Chinese Female Weightlifters

Objectives:This paper analyzes the technical movements of China's female weightlifters,and reveals the internal relationship between performance and technical indicators in snatch.It can provide a theoretical basis for technical evaluation of the lifting,also is conducive to improve the performance of competitive weightlifting and promote the innovation of sports technology through the quantitative analysis of a large number of excellent samples to obtain the specific value range of technical indicators.Methods :A total of 106 Chinese female weightlifters were selected in this study,including 18 in the 48 kg category,17 in the 53 kg category,20 in the 58 kg category,17 in the 63 kg category,11 in the 69 kg category,11 in the 75 kg category,and 12 in the 75+ kg category.A total of 25 first-level athletes,55 athletes,26 international athletes.The "weightlifting real-time evaluation and feedback system" was used to obtain the kinematics data of athletes in the process of snatch,and then the data of athletes of different competition levels and sports levels were analyzed and studied separately.Results:(1)The relationship between the athlete's height and the height of the barbell when driving force.The model is Y=0.734x-0.465,R=0.750.The relationship between the athlete's height and the barbell height at the maximum barbell speed.The model is Y=1.167x-1.027,R=0.722.The relationship between the athlete's height and the barbell height at the maximum barbell height.The model is Y=0.920x-0.295,R=0.843.(2)The relative height of the barbell in the lifting phase: the ratio of world-class athletes is 9.53±5.7%,the national athlete is 7.4±3.5%,The ratio of the first-grade athletes is 7.3±4.9 %.(3)The relative height of the barbell in the second pull phase: the ratio of world-class athletes is 9.53±5.7%,the ratio of national athlete is 7.4±3.5%,the ratio of the first-grade athletes is 7.3±4.9 %.(4)The barbell during the inertia rise: the ratio of world-class athletes is 20±7%,the ratio of national athlete is 22±5%,the ratio of the first-grade athletes is 22±4%.(5)The relative distance of the barbell fall in the squat support phase: the ratio of world-class athletes is 9.9±2.1%,the ratio of national athlete is 10.9±2.4%,the ratio of the first-grade athletes is 10.6±2.1%.(6)In the second pull phase,the relative height ratio of the barbell rising for the 75+ kg athletes is 13±8 %.In the inertia rising phase,the relative height ratio of the barbell rising for 75+ kg athletes is 18±8 %.During the squat support phase,the relative distance ratio of the 75+ kg athletes to fall off the barbell was 8±1 %.(7)The barbell speed change in the second pull phase: The speed of world-class athletes is 0.23± 0.13 m /s.The speed of national athlete is 0.24± 0.19 m /s,the speed of the first-grade athletes is 0.17± 0.11 m /s.(8)As to a inernational athlete: the horizontal displacement of the barbell is 11±20 mm.,the maximum time of bell speed is-20±28 mm,the maximum moment of bell height is 37±45 mm.The supporting point is 110±60 mm at the moment.Conclusions:(1)The height of athletes is positively related to the group of competition.The height of an athlete is linearly related to the height of a barbell in each stage.The linear model can help the athletes to calculate the height of barbell in each stage when they try to lift the ultimate weight.(2)In the lifting stage,the higher the technical level of the athletes,the shorter the distance of the barbell rising,and the more consistent the connection between the lifting and the exertion.This index can be used to evaluate the ability of lifting the bell and the skill of generating force.In the pull stage,the higher the technical level of the athletes,the greater the change of the relative height of the barbell.This index can be used to evaluate the pulling ability of the athletes.In the stage of inertia rising,the higher the technical level of athletes,the smaller the relative height of barbell inertia rising.This index can be used to evaluate the lifting ability of athletes.In the squat supporting phase,the higher the technical level of athletes,the smaller the relative distance of the barbell fall.This index can be used to evaluate the ability of receiving the barbell.(3)In the three stages of starting force,inertia rising and squatting support,there are significant differences in the relative distance of barbell movement between the 75+ athletes and other athletes,reflecting different technical characteristics.(4)In the stage of power generation,the higher the technical level,the greater the change of the barbell speed.This index can evaluate the technical level of athletes.(5)The movement range of barbell is more reasonable.The barbell trajectory of the athletes in the small kg category is more ideal,in line with the characteristics of the "s-shaped" curve.