Effect Of Lateral Entry Technique On Crouching Start Of Chinese Elite Swimmers

Competitive swimming consists of four parts:departure,turn,swim en route and sprint to the side.Departure,as the first part of the swimming competition,is crucial for athletes,which accounts for 0.8%-26.1%of the competition time depending on the distance of the event.Especially in short-distance swimming events,there is usually a minuscule gap between medalists,and a tenth of a second or even a hundredth of a second can change the final result,so the improvement and research of swimming departure technique is getting more and more attention.At the same time,with the development of the times swimming technology is also progressing and constantly updated.Throughout the history,swimming departure technology is being updated in this environment.This study takes the departure entry mode of swimmers as the entry point,through 8 weeks of lateral entry technique training intervention for high-level athletes,and through the comparison of the bio-mechanical indexes(including kinematic and kinetic indexes)of each stage of the departure technique measured before and after the experiment,analyzes and summarizes the influence of lateral entry technique on squat departure,aiming to explore the differences between lateral entry technique and forward entry technique,find out the advantages of lateral entry technique,so as to provide a theoretical basis and practical basis for the application of lateral entry technique in the competition,and also provide a new idea for improving the departure speed.In this paper,12 high-level swimmers in China were trained by literature,expert interview,experimental method,video analysis and mathematical statistics to intervene in the squatting departure and water entry technique,and the athletes’squatting departure was analyzed by the bio-mechanical indexes before and after the experiment into the departure preparation stage,departure stage,vacating and water entry stage,underwater gliding stage and water exit stage,and the following conclusions were drawn.The lateral entry technique has no significant effect on the performance from the start to 15m,but it will have an effect on the time ratio of each phase from the start to 15m,increasing the proportion of the underwater gliding phase of the crouching start and shortening the proportion of the water exit to 15m phase;there was no significant effect of the lateral entry technique on the departure preparation phase of the squatting departure;the lateral entry technique would increase the stagnation time of the squat start,but would increase the horizontal speed at the moment of leaving the stage and would allow the athletes to leave the stage with a smaller body tilt angle and a farther center of gravity position;the lateral water entry technique increased the peak horizontal force of the front stirrups and thus the peak horizontal force of the squatting start in the offstage phase;the lateral entry technique would result in a certain lateral tilt angle(34.17±9.60°)in the water entry phase of the squatting departure,and would also increase the water entry distance,and also increased the maximum depth of water entry and the distance to the maximum depth;the lateral entry technique delayed the athletes’ first underwater leg time while making them first underwater leg at a deeper depth and further distance,thus effectively increasing the length and proportion of the athlete’s underwater glide;the lateral entry technique causes the athletes to exit farther in the water exit stage The water exit time was also delayed,thus also reducing the length and proportion of the water exit to 15m phase.