| Objective: From the perspective of kinematics,this study conducted a comparative analysis of the kinematic parameters such as lower limb joint angle,joint velocity,center of gravity trajectory changes and other changes in the process of completing C715 difficult movements,aiming to preliminarily explore the technical characteristics and kinematic laws of C715 difficult movements,compare the technical differences of athletes of different levels,and provide reference for the teaching and training of difficult movements.Methods: In this study,the motion infrared light spot high-speed motion capture system was used to collect kinematic data from 8 competitive aerobics athletes(4 at high level and 4 at ordinary level)from Capital Institute of Physical Education to complete C715 difficult movements,preprocessed the collected data through Cortex software,sorted and calculated the data by Excel,compared the movements of the high-level group and the ordinary level group in depth,and used SPSS software to conduct independent sample T test.Results:1.The difference in the time taken by the two groups to complete each stage of the action was mainly in the reduction upright stage,and the high-level group took longer time and had a higher degree of completion of the action.2.The hip angle change of the high-level group in the pre-swing stage was more consistent,the combination of pre-swing and rotation was better,and the upper limb swing speed was faster at the end of the stage;The ordinary horizontal group is prone to problems such as incoherent pre-swing and rotation,and poor pre-swing posture.3.The angle of free leg hip and knee joint of the two groups did not reach the standard,and the ankle joint and left upper limb speed decreased rapidly in the ordinary horizontal group,and the left upper limb speed was quite different at the end of the stage.4.The flexion and extension angle of the free leg hip joint in the 360°stage of leg control and the reduction upright stage was greatly different from the standard angle,the angle of the knee and ankle joint changed greatly,and the height of the center of gravity decreased rapidly.Conclusions:1.Ordinary level athletes do not have obvious leg control during the rotation process,indicating that the strength of the flexor muscles of the free legs is insufficient,and the ability to control the angle of the knee and ankle joints also needs to be strengthened.2.Highlevel and ordinary level athletes have the phenomenon of heel landing during the rotation process,and it is necessary to strengthen the stability of the supporting leg and ankle joint.3.The trajectory of free leg swing of high-level athletes is relatively consistent,indicating that after years of training,the swing leg technique of athletes is basically fixed.4.The change of upper limb swing speed and swing leg of high-level athletes are better combined with the swing leg,which is more conducive to the completion of the action.5.The change trend of the center of gravity of high-level and ordinary level athletes is basically the same,but the displacement of the center of gravity of ordinary level athletes in the turning stage is more obvious,and it is easy to make movement errors. |
