A Study On Biomechanics And EMG Character Of The Racing Wheelchair "Butterfly" Technique

Objectives:The paper want to research and analysis on the movement structural features of "butterfly" technique,and to study on the motion characters of the head and the every joints of the upper limb how to effect on the speed of the wheelchair,and to study on the exerting force and doing work of the main muscles of the upper limb and the truck during a pushing cycle.Through biomechanics methods to elucidate racing wheelchair characters which the man-machine integration,and to provide the certain theoretical basis for scientific training of the "butterfly" technique and prevent carpal canal syndrome.Methods:By using High-Speed Camera and real-time EMG to fixed point tracking test for six man athletes and four woman athletes of the national team.Based on the Kwon3D motion analysis system that made in Korean to analysis the images and obtained the kinematic parameters of the main segments.Collecting and Analysis the EMG are used Megawin6000 Instrument and MegaWin 2.3a12 software which all made in Finland.And EMG combined with segment force analysis to described detailedly.The data of the kinematic and EMG used SPSS15.0 to do Statistics Analysis.Conclusions:(1)In the shove phase,the speed order from fast to slow are elbow joint,shoulder joint and wrist;and the speed order from fast to slow are wrist joint,elbow joint and shoulder joint in the get return phase.(2)Through the Bivariate Correlations,the acceleration of the head assumed high correlation with the center of the back wheel, significant correlation with the shoulder joint,a weak correlation with the elbow joint,and low correlation with the wrist joint in the positive direction of sagittal plane during the shove phase.While the acceleration of the head showed a weak correlation with the shoulder joint, the elbow joint and the wrist,but the correlation coefficient were negative among the acceleration of the head,the shoulder joint and the elbow joint in the positive direction of sagittal plane during the get return phase.(3)Through the Partial Correlations,in the positive direction of sagittal plane,the high correlation was found in the speed of the elbow joint and the wheelchair during the shove phase,while the speed of the upper limb link and the wheelchair showed perfect linear correlation in the get return phase.(4)By using EMG and segment force analysis,as the antagonistic muscles of the flexor carpi radialis and the redial extensor carpal muscle it showed significant activity according to the main segment effect during a pushing cycle.The triceps and the biceps brachii gives the greatest contribution to the total iEMG,it was regard as main exerting force muscles.(5)In Theoretical Mechanics,there exits main influencing factors as following:thrust forces,the torque which the hand imposes on the wheel,the wheelchair mechanics,the Rolling Friction Force,the Air Resistauce,the Internal Friction Force and so all.All the analysis shows that the athletes may do specialized endurance training of the triceps,the biceps brachii,the flexor carpi radialis and the redial extensor carpal muscle to improve endurance levels according to the characters of the racing wheelchair.In addition,the athletes may strength muscles of the flexibility training and the strength training during the dynamic balance environment aroud the every joint.Besides specialized training,theoretical scientific research personnel may use advanced simulation means to make racing wheelchair more humanity.