Research On The Characteristics Of Kinematics And Surface Electromyography Of 324B+1 In Male Martial Arts Routine Athletes

Research purposes: The purpose of this study was to analyze the characteristics of the kinematics of joints and surface myoelectric activation of muscles related to the trunk and lower extremities from eight men’s martial arts routine student athletes during the 540 ° hurdle swing in order to provide better guidance of athlete training.Research Methods: Using kinematics and surface electromyography to investigate the movements of body center of gravity,hip,knee and ankle and activation characteristics of 12 muscles,including left and right external oblique muscles,rectus femoris,femoral medial muscle,biceps femoris,tibialis anterior muscle,and gastrocnemius muscle,respectively.Three high-speed cameras were used to capture the kinematic variables during the operation and observe the entire experimental process.A surface electromyography(EMG)tester was used to obtain the activation level of 12 muscles.The variables included the spatio-temporal index of the run-up phase,the positions of the body’s center of gravity,the angles and angular distances of hip,knee,and ankle joints at different stages of take-off and air phase,and the integrated electromyography and its contribution rate.Results: it was showed that the average step length was 1.02 ± 0.28 m,the average step length was 1.32 ± 0.34 m and the total step length was 2.32 ± 0.40.The maximum time spent on the run was 1.28 ± 0.23 s,while the take-off and landing times were 0.52 ± 0.07 and 0.54 ± 0.08 s,respectively.The time to take-off was 0.61 ± 0.09 s.Pre-squat support buffer stage,the lowest point of the body center of gravity,extension time,after the toe off and again at the moment of landing and the lowest point of body center of gravity positions were 1.04 ± 0.12,0.69 ± 0.11,1.19 ± 0.14,1.12 ± 0.13 and 0.61 ± 0.09 m.The maximum angular displacements of the left and right hips in the support buffer stage were-51.05 ± 7.72 and-48.25 ± 6.33 °,respectively;the angular displacements of the hip and ankle joints in the extension stage were significantly increased by 100.31 ± 18.03 and99.95 ± 19.54,87.66 ± 14.53 and 77.72 ± 12.09 °,respectively.The angular displacement of the left hip joint in the ascending stage was significantly smaller than that of the right hip joint,and the angular displacements of the hip and ankle joints were larger in the landing stage.The muscle integrated Electromyography(IEMG)of the rectus femoris muscle in the run-up stage was significantly greater than that of other muscles.The IEMG of the left rectus femoris muscle was greater than that of the right rectus femoris muscle.The IEMGs of left and right biceps femoris and tibialis anterior muscle in the support buffer stage were significantly higher than other muscles,while the IEMGs of the rectus femoris muscle and medial muscle in the extension stage were higher.During the air stage,the IEMGs of the right rectus femoris muscle was significantly greater than that of the left hip joint.The IEMGs of the anterior tibialis anterioris and biceps femoris muscles during the landing stage were significantly higher than that of the other muscles.Conclusions: The proportion of run-up time in the total time was the highest,while the time difference between take-off,air and landing was not obvious.324 B +1 movement of the six characteristics of the body when the height of the center of gravity showed different forms of change.In terms of joint angle indicators,there were some differences in different stages;however,they were all dominated by the movement of the hip joint.In the surface EMG indicators,the activation levels of the rectus femoris,tibialis anterior and biceps femoris at different stages were relatively higher than other muscles.Based on these findings,it was suggested to enhance the flexibility training of the hip joint to increase the magnitude of the 324 B + 1 action and increase the expressiveness of the movement.In addition,it was to strengthen the muscles around the lower extremities and trunk activation training,especially the rectus femoris,biceps femoris and tibialis anterior muscle.Through concentric and eccentric training,these muscles were increased to synergistically activate at different stages of the 324 B + 1 action to improve the quality of the movement.