Kinematic Analysis Of Turning Techniques Of My Country's Outstanding Male Freestyle Swimmer

In recent years,our country and even the world’s competitive swimming level is increasing continuously,more and more world records were broken and updating,human swimming speed is closer and closer to the limit of human physiological endurance range,and even will reach the limit of the human body.Therefore,for competitive swimming events,the improvement of skills will become the focus of training.At the same time,a number of excellent athletes have emerged gradually in competitive swimming in our country.In spite of this,the overall level of Chinese competitive swimmers is in a disadvantaged position.With the rapid development of men’s freestyle events,turning technique is one of the important factors affecting the athletes’ freestyle performance.Scientific and reasonable turning techniques can increase the motivation for athletes to achieve more excellent results.The closer the competitive level is,the more the quality of the turning technique can affect the athletic performance.Therefore,the turning technique is also an opportunity to surpass the opponent in the competition.By making good use of the speed brought by the turning,the athlete can finish the race faster and open the distance between him and the opponent.Based on the special characteristics of the water environment in which competitive swimming is conducted,and in order to make up for the relative lack of kinematic methods in domestic swimming,this paper takes the turning technique of China’s outstanding male freestyle athletes as the object of study.The test subjects of this study are two of China’s outstanding male freestyle athletes,both of whom are international athletes and have won national championships.Using the method of analysis by turning force measuring table and underwater high-speed synchronous camera analysis,the data of 15 m turning phase of the athletes were obtained,from which the kinematic and some kinetic parameters of the two athletes were compared and analysed,and SPSS26.0 software was used for correlation analysis.The correlation analysis was carried out to identify the deficiencies of the two athletes’ turning techniques and to compare them,to find out the correlation factors between the indicators of the two freestyle athletes’ turning phases,to provide accurate opinions on individual turning techniques for the athletes and coaches,and to provide data support for the coaches’ future training plans,as well as to provide scientific data reference for the targeted and personalised improvement and optimisation of the two athletes’ freestyle turning techniques,which enables The athletes will be able to improve their performance and achieve better results,as well as to improve their individual level of athletic ability to a certain extent.The following conclusions were obtained from the analysis of this study:(1)Swimming into the wall stage: Athlete A1’s swimming speed is relatively fast,and there is no obvious deceleration before turning,which is a good completion.At the end of the last stroke,athlete A2 had an obvious slight upward movement,which missed the best turn time,affected the effect of the turn,reduced the swimming speed,and made the connection of this stage incoherent.(2)Turning stage: Athlete A1’s group movement in the process of turning is not compact enough,which makes the rolling time longer and the consistency is not strong,thus affecting the effect of turning to touch the wall.Athlete A2’s turn takes too long to touch the wall,resulting in less force and work done during the push off.(3)Stomp phase: Both athletes have shallow stirrups and are not able to coordinate their efforts well.Athlete A1’s stirrups were faster and his instantaneous explosive power was higher than that of athlete A2,resulting in a higher peak power.The angle of body tilt at the moment of stirrup departure was not significant,thus affecting the time out of the water,which was negatively correlated with the time out of the water.The knee angle was not very different from the findings of the previous study,but the hip angle was relatively small,thus also affecting the profound body tilt angle at the moment of stirrup departure,resulting in a relatively longer underwater glide time and a slower underwater glide speed,which also affected the effect of the underwater butterfly leg to a certain extent,making the athlete’s exit time shorter and therefore resulting in a closer distance out of the water.Athlete A2 had a relatively slow stirrup-off speed,which affected the power values,but his stirrup-off moment inclination angle,knee angle and hip angle were better,reducing the wave resistance in the underwater glide phase and allowing athlete A2 to complete the underwater glide phase in a depth with less resistance.(4)Gliding stage: Athlete A1 has high gliding resistance,fewer underwater butterfly leg times and small underwater butterfly leg bend Angle,leading to premature exit time.Athlete A2 has more underwater butterfly legs compared to athlete A1,but there is still a gap compared to the world’s best athletes.(5)Exit stage: the two athletes’ exit time is earlier.Athlete A1 had fewer butterfly legs underwater,so he had to get out of the water early,but he had strong explosive power,which could be well connected with his exit speed.The number of strokes A2 can be increased to complete the stroke at the appropriate depth.(6)Overall turning technique: athlete A1 has the best technique of turning 15 meters.Because the total time of turning 15 meters represents the performance of complete turning technique,therefore,in freestyle turning technique,athlete A1’s turning technique is better than athlete A2’s turning technique.(7)The roll time was negatively and significantly correlated with the time of turning to touch the wall.Swim-in speed and stirrup-off speed,swim-in speed and underwater glide speed,and underwater glide end speed and swim-out speed were all significantly and positively correlated.