Kinematics And Surface Electromyography Analysis Of Spiral Rotational Rope Releasing Technique Of Different-Level Fancy Rope Skippers

Research purpose: This dissertation mainly uses the related knowledge of kinematics and surface electromyography to analyze the motion rules and technical characteristics of the spiral rotational rope releasing technique of fancy rope skippers.By comparing the differences between the two groups of subjects in the process of practicing the spiral rotational rope releasing technique,and find out the deficiencies in the movements of the low level group of subjects,so as to improve the practice efficiency and avoid unnecessary sports injuries,and provide a theoretical basis for the coaches and athletes to improve the spiral rotational rope releasing technique.Research methods: This dissertation mainly uses the methods of literature,expert interview,testing,mathematical statistics and comparative analysis.Three H6Z0812 M high-speed cameras are used for image shooting,and the Italian BTSFREEEMG wireless surface electromyography is used to collect the activation status of 12 upper limb muscles of six high-level and six low-level subjects during the practice of spiral rotational rope releasing technique.The kinematics and s EMG data are analyzed by SIMI MOTION software and Emg Server3.0 software.The following results were obtained through the test:Research results:(1)The releasing angle between the hand and the rope handle(at this moment the rope is thrown out)of the high level group is 128°;the releasing speed is3.56m/s and the releasing height is 0.97 meters.The time of connecting the rope is 2645milliseconds;its angle is 44°;its speed is 3.53m/s;and its height is 1.06 meters.(2)In the pre-swing phase,the two groups both have the largest contribution rate of the anterior deltoid of the right arm,with 29.63% in the high-level group and 31.05% in the low-level group.In the first round of the semi-gripping stage,the largest contribution rate of the middle deltoid of the right arm in the high-level group is 26.89% and the largest contribution rate of the anterior deltoid in the low-level group is 33.19%.In the second round of spiral-throwing rope,the largest contribution rate of the right arm’s trapezius in the high-level group is 28.22% and the largest contribution rate of the anterior deltoid in the low-level group is 31.73%.In the rope connection stage,the largest contribution rate of the right trapezi us in the high-level group is 35.2% and the largest contribution rate of the anterior deltoid in the low-level group is 42.55%.Research conclusions:(1)The main reason why the rope releasing technique of the low-level group is longer than that of the high-level group is that it takes too long to release the hand in the grip phase.The order of the proportion of time in each stage of the high-level group is: pre-swinging stage>semi-gripping stage>rope connecting stage.The best time to release the rope should be one-half of the total duration of the action.(2)The low-level group moves the center of gravity toward left faster than the high-level group.The overall joint speed of the arms is slower and the joint angle is large.(3)The movement direction of the right arm and right hand in the low-level group is wrong.The speed of the right hand of the low-level group is slower than that of the high-level group.(4)The overall level of muscle activation in the high-level group is higher than that in the low-level group,and there is a difference in the main muscles between the two groups.According to the above conclusions,the author suggests that the invalid movement track of the arm should be appropriately reduced and the overall speed of the arm should be increased when practicing the spiral rotational rope releasing technique.The timing and position of the left hand rope releasing and the coordination between the two arms should be paid attention to.In the semi-gripping stage,the arm should continue to do centripetal movement to facilitate the connection of the rope.The speed of releasing rope should be increased,and the speed of connecting rope should be reduced.The upper limb muscles should be used correctly to adjust the main muscles of the arm.