| Research aims and research significance:To explore the technical characteristics of the run-up and take-off stage of outstanding women long jump athletes in China,to explore the relationship between the technical stability of long jump and competition results,and to further improve the sports biomechanical mechanism that affects the performance of long jump competition.Research subjects:All the top 8 athletes in the female long jump final of the 2019 National Indoor Athletics Championships were successfully tested.Research methods:The top 8 athletes of women’s long jump in the final of the 2019 National Indoor Athletics Championships were selected and analyzed with the video footage of all their successful trial jumps,a total of 36 trials.Results:(1)The length of the last two steps of 6 runners in the run-up to the race is in a "big-small" change mode,while 2 runners are in a "small-big" change mode.There was a significant difference between the excellent group and the ordinary group in the stability of the second step length,P < 0.05,and the ordinary group was more stable.The stability of backward step length has a positive linear relationship with the change rate of step size.(2)The speed of the last two steps in the run-up to running in the excellent group was 9.78±0.18m/s and 9.44±0.13m/s,respectively,which were significantly higher than that in the ordinary group(9.42±0.16m/s,P < 0.01)and 9.14±0.1m/s,respectively(P < 0.01).With the improvement of the performance,the stability of speed in the last two steps increases first and then decreases,and there is a negative linear relationship between the stability of speed reduction and the best performance.(3)The buffer time of elite athletes was 0.031±0.013 s,significantly lower than that of ordinary athletes,which was 0.042±0.009 s.The stability of step and jump time was positively correlated with the best performance.(4)There were significant differences between the elite group and the ordinary group in the hip Angle at the moment of lift,the knee Angle at the moment of maximum cushioning and the stability of the hip Angle at the moment of maximum cushioning.(5)With the improvement of performance,the ankle-knee and knee-hip coordination variability of the take-off leg decreased first and then increased,and the fitting curve was a quadratic equation with an upward opening,while the ankle-knee and knee-hip coordination variability of the swing leg showed a negative linear relationship with performance.(6)In the excellent group,the Angle between the thighs was 93.49±5.63°,and the fan Angle was 44.7±4.56°,which were significantly lower than those in the normal group(98.48±7.81° and 49.53±5.66°),while the Angle of the ground in the excellent group was significantly higher than that in the normal group.There are significant differences between the excellent group and the ordinary group in the stability of landing Angle and stepping Angle,and the excellent group has better stability.The stability of landing Angle,stepping Angle and fan Angle are all positively correlated with the performance.Conclusions:(1)Athletes with the last two steps of run-up rhythm as “length-short” change mode have higher stability than athletes with “short-length” rhythm.For athletes with“length-short”change mode,the greater the change rate of step size,the lower the stability of inverted step size.(2)As for stability,the last two steps of Chinese women’s long jump athletes’ speed stability and competition results show a “U”curve trend,that is,the athletes with better results and the athletes with poor results have lower stability of run-up speed.The stability of run-up speed is higher.But the speed reduction quantity stability shows the better the result,the higher the speed reduction quantity stability.Excellent athletes will be more bold in the run-up stage to play their own speed ability,so that their run-up speed to maintain a higher level,but they pay more attention to the stability of speed change,maintain a stable run-up speed structure,More conducive to full take-off.(3)Most women’s long jumpers in China have unreasonable time allocation,too small conversion time and too large buffer time.The buffer capacity is weak when stepping,so the run-up speed can not be effectively converted into horizontal speed and vertical speed,and the speed loss is large.(4)At present,most women’s long jumpers in our country have unstable and unbalanced development in take-off technology.The vertical velocity can not be properly coordinated with the vertical velocity.The take-off technique with small braking and relatively small horizontal speed loss rate is more suitable for the specific characteristics of Chinese women long jump athletes.(5)There is a “trend line of U” font between the coordinated variability of ankle-knee joint coupling and knee-hip coupling in women long jump athletes in China.Athletes with poor performance only obtain surface characteristics consistent with the mode of exercise,and this high variability is unfavorable to sports performance;athletes with moderate grades show low variability by refining this surface feature;Athletes with better performance have higher variability because of the increased flexibility of the sports system,which is conducive to resistance to interference.The coordination variability of knee-hip coupling in athletes with better results is much smaller than that in athletes with poor results because the swinging legs are not more disturbed than the take-off legs,and there is no need for more flexibility to resist interference.(6)The angle of landing and the angle of pedaling in the take-off stage of women’s long jump athletes in China is small,and the angle of fan face is too large,which leads to too long buffer time,incoherent movement,too large loss of horizontal velocity and small vertical velocity.(7)The relationship between the athlete’s technical level and stability is consistent for the angle of touchdown,the angle of toe-off,the sector angle and the take-off time. |
PDF Full Text Request