Experimental Study On The Effect Of Bi-fins Training Methods On Underwater Dolphin Kick Technique Of 12-14 Years Old Youth Swimmer

Competitive swimming has always been one of China’s diving advantages,but there is still a big gap between the Chinese swimming team and European and American swimming powers in terms of competitive strength.The "14th Five-Year Plan" sports development plan points out that it is necessary to tap and cultivate potential advantage projects.Vigorously develop the basic disciplines of athletics and swimming,and establish a scientific and effective training system.underwater dolphin kicks in swimming are the key technology for athletes to improve speed after starting and turning,FINA regulations: athletes are allowed to do one or more underwater dolphin kick strokes within 15 meters after starting and each turn.This means that the swimming distance of the underwater dolphin kick can account for up to 30% of the total distance,and the proportion of the short pool competition can be as high as 60%.The technical movements of the fin swimming event are highly similar to the underwater dolphin kick technique in the swimming event,and China’s competitive fin swimming has always maintained the highest competitiveness in the world.Combining the bi-fins technique in fin swimming with underwater dolphin kick training is conducive to improving the underwater dolphin kick technique of youth swimmers,thereby improving swimming performance.Through reading and summarizing the literature of predecessors and sorting out the results of expert interviews,the evaluation indicators were determined for this experiment and the experimental hypotheses were proposed.The 12 young male swimmers of the Nanning swimming team in Guangxi were randomly divided into experimental group and control group,and a total of 12 weeks of double-finned intervention training and regular training plans were formulated for them,and the changes in underwater dolphin kick technique and short-distance freestyle performance in the three stages of the test athletes before,during and after the experiment were compared and analyzed,and it was determined which bi-fins training method could bring to the athletes’ underwater dolphin kick skills,so as to help athletes improve their underwater dolphin kick ability.Optimize underwater dolphin kick technology.Specific training contents include:(1)vertical bi-fins dolphin kick training;(2)Sticking to the bottom of the pool double webbed butterfly swimming leg training;(3)Double webbed anti-dolphin kick training;(4)Armrest bi-fins dolphin kick training;(5)Maximum speed bi-fins underwater dolphin kick training.The Go pro Hero 9 action camera was used to record the 15-meter underwater dolphin kick test of the athletes at each experimental stage,and the evaluation indicators were analyzed by Dart fish sports video analysis software.Combined with the training plan,the changes in the test data of the 12 tested athletes were analyzed and the following conclusions were drawn:1.Through the training methods such as vertical bi-fins dolphin kicks,bi-fins anti-dolphin kicks and buttressed bi-fins dolphin kicks,the range of movement of the legs and the flexibility of the shoulder joint can be effectively improved,so that the athletes can ensure the stability of the upper body and the streamlined shape of the body posture when swimming the underwater dolphin kick.2.Specialized bi-fins intervention training can effectively improve the leg strength of athletes,but it is easy to use quadriceps muscles to compensate for underwater dolphin kick test after taking off both fins,resulting in no significant improvement in the amplitude of athletes’ leg hits.3.The training method of bi-fins underwater dolphin kick has a significant impact on improving the flexibility of athletes’ ankle joints,increasing the load on the ankle joint when athletes hit legs by wearing fins,and improving leg fighting techniques while increasing the strength of the lower limbs.4.Training methods such as bi-fins dolphin kicks and bi-fins anti-dolphin kicks at the bottom of the pool can effectively improve the knee angle and leg frequency of athletes’ underwater dolphin kick,and improve muscle proprioception while correcting the technical movements of underwater dolphin kick.5.Training methods such as vertical bi-fins dolphin kicks and maximum speed bi-fins underwater dolphin kick can improve the explosiveness and speed endurance of athletes’ lower limbs while maintaining the streamlined shape of body posture,and improve the short-distance performance of young swimmers.Scientific training has always been an important part of competitive sports.It is recommended that when using double fins as auxiliary equipment for underwater dolphin kick training,corresponding training methods should be adjusted according to the different main points of athletes,targeted training should be carried out considering the individualization of athletes,and attention should be paid to controlling the dependence of young swimmers on fins to avoid the loss of water sensation when swimming in freehand due to excessive use of fins during training.