| Research purpose: Chinese athletes have a great advantage in women 55 kg weightlifting.This study mainly uses kinematic analysis method to analyze the snatch technical movement of athletes in order to reveal the snatch technical characteristics of Chinese female weightlifters.To find out the technical shortcomings of athletes and diagnose the rationality of athletes’ technical movements,which provides theoretical reference for athletes and coaches.The Research object and methods: The top eight female weightlifters of 55 kg class in 2020 National Weightlifting Championships and Tokyo Olympic Trials were selected as research objects,and their sports levels were international elite and athletic elite.The average age of the subjects was 23.In this study,two ex-FH25 Casio high speed cameras were used to take 3d fixed focus shots of snatch movements of eight athletes in the competition.Then,the APAS 3D motion analysis system produced by ARIEL was used for kinematic analysis.Finally,Excel and SPSS26.0 were used to sort out and analyze the data obtained from the analysis.Results:The mean hip Angle and standard deviation were 59.17±6.14°,the mean knee Angle and standard deviation were 77.33±6.93°,and the mean ankle Angle and standard deviation were 86.41±4.03°.The mean and standard deviation of hip Angle,knee Angle and ankle Angle were 92.41±7.800°,123.2±6.150° and 101.5±6.080°,respectively.The mean and standard deviation of hip Angle,knee Angle and ankle Angle were 135.7±13.63°,113.3±5.911° and 94.50±9.33°,respectively.The mean and standard deviation of hip Angle,knee Angle and ankle Angle were169.2±3°,151.1±8° and 130.9±11.62°,respectively.The mean hip Angle and standard deviation were 118.1±17.03°,the mean knee Angle and standard deviation were73.86±6.52°,and the mean ankle Angle and standard deviation were 73.02±8.97°.The mean hip Angle and standard deviation of eight athletes at the lowest barbell height were 66.02±10.27°,the mean knee Angle and standard deviation were 41.04±4.44°,and the mean ankle Angle was 75.35±6.02°.The mean and standard deviation of the distance between two heart of eight athletes at the moment when the barbell lifted from the ground was 0.31±0.02 m,the maximum moment of knee extension was 0.26±0.02 m,the maximum moment of knee induction was 0.17±0.02 m,the maximum moment of bell speed was 0.15±0.02 m,and the highest point of the barbell was 0.49±0.02 m.The lowest point of barbell is0.59±0.03 m.The average barbell fall distance of the eight athletes was 18.1± 3.6cm.The mean value and standard deviation of barbell vertical velocity were 0.87±0.13m/s in the stage of knee extension and lifting,0.42±0.2m/s in the stage of knee lead and lifting,and 0.4±0.21m/s in the stage of driving.The mean value and standard deviation of barbell vertical velocity were 1.65±0.35m/s in the inertial rise stage,and0.26±0.26m/s in the squat support stage.Conclusions:1.From the moment when the barbell lifted off the ground to the moment when the knee was drawn out,the distance between the two centers was smaller,which reflected the technical feature of "close" in snatch.2.China’s 55 kg elite female athletes all show strong explosive power and good effect in the power generation stage.There is a significant positive correlation between the result and the maximum instant hip Angle and knee Angle of barbell speed.3.Chinese 55 kg elite female athletes all show the technical characteristics of large hip Angle at the end of squat support.The greater the hip Angle,the greater the distance between the barbell center of gravity and the barbell center of gravity,so that the barbell center of gravity is difficult to control because of the back of the snatch.4.Eight athletes showed the technical characteristics of small knee introduction amplitude in the stage of knee lifting.When the highest point is reached on the barbell,the vertical velocity of the barbell of all eight athletes is close to zero.Li Yajun did not extend the hip enough in the power generation stage,which affected the power generation effect.5.Kang Zhengmei fully extended her knee at the maximum moment of knee extension with good power generation,and fully extended her hip at the power generation stage.Luo Shifang and Yu Linglong had relatively small knee extension Angle and insufficient knee extension movement.There was a significant positive correlation between their performance and the maximum instantaneous hip Angle of knee extension. |
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