| Compared with other sprints,the 400 m event has the longest distance to maintain a high speed.At the same time,the athlete's body bears the most load,which is equivalent to running 4consecutive 100 m high-intensity exercises.The young female 400 m athletes are the reserve force of my country's women's 400 m event and are related to the sustainable development of the women's 400 m event.Their speed and speed endurance reserves are insufficient,and the most important thing is that the pace of the whole journey is not stable and reasonable.Step length and step frequency are the two major factors affecting speed.Discover and understand the changing law of step length and step frequency of young female 400 m athletes.Through reasonable control of step length and step frequency,we can optimize the speed distribution in the game and improve the young women's speed.The rationality of the athletes' full speed rhythm in the 400 m event allows them to play their best speed level.This article analyzes the collected videos of the 14 th Shandong Provincial Student Games(Middle School Group)in 2019,the 2019 National Youth Athletics Championships,and the2016 National Athletics Championships Women's 400 m Finals,using documentary data method,video analysis method,and mathematical statistics.Research methods such as method and comparative analysis method.Kinematics such as 30 young women(15-18 years old)400m athletes who reached the national level of second-level athletes in the youth 400 m athletes competition,and 8 athletes in the women's 400 m finals of the 2016 National Athletics Championships.The data is the research basis,and by comparing the difference in step length and step frequency control and speed distribution between the young female 400 m athletes and the adult female 400 m athletes,it is found and understood that the young female 400 m athletes step frequency and step length change law,for the young female 400 m athletes Athletes provide a new reference basis for step length and step frequency control and optimization of speed rhythm.Found in study:1.The full cadence of the female 400 m athletes in the youth group gradually increased during the acceleration phase of the start,and generally reached the highest cadence at 12-16 steps,and then fluctuated and decreased within a certain range,and the unit cadence dropped drastically in the last 8 steps.The lowest cadence occurs during the finish line collision phase.The rhythm of the step frequency of the young female 400 m athletes is not reasonable enough.The average step frequency of the first two 100 m segments is too fast,and the proportion of the step frequency used in the front and the back half is quite different,resulting in a significant drop in the step frequency in the sprint phase.2.The speed of the fourth 100 m segment of the young female 400 m athlete is highly significant and positively correlated with the step length.The pace of the step length is unreasonable.The relative step length utilization rate of the first two 100 m segments is too high,and the athlete cannot step in the second half.In the case of a large drop in frequency,the speed is maintained by the step size.The female 400 m athletes in the youth group and the adult group have gaps in step length and step frequency reserve,but the difference in step length reserve is the more important reason for the difference in performance.3.Unreasonable step frequency and step length rhythm of young female 400 m athletes lead to unreasonable speed rhythm.The speed level difference between the 4 segments is large,the first 100 m overaccelerates,the second 100 m segment is too fast,the first The speed of the three100 m sections is much lower than that of the first 100 m,and the speed of the fourth 100 m section drops significantly.4.The coefficient of variation of step frequency,step length,and speed of the young female400 m athletes is relatively large,and the step frequency,step length,and speed fluctuate greatly in the whole course,which causes excessive energy consumption. |
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