The Computer Aided Analysis For Joint Chains Of Upper Limb Whiplash Movement In Tennis Serve

PuposeThe influence of the elbow joint angle and the wrist angle change on the terminal velocity in the upper limb of the tennis serve is explored.The relationship between the different elbow joint angles and the wrist angle changes and the rotational inertia of the upper limbs is analyzed,and the end kinetic energy is calculated,and the general rules of the whipping are analyzed,which can be obtained for the tennis players.It provides a reference for maximum hitting speed.MethodsThis research mainly use the methods of documentation,experi mental measurement,software engineering.1)The document method is as follows: through the datab ase of the Liaocheng University library,the Chinese academic jour nal network,EBSCO and so on,the retrievalwords are called "wh ip","tennis serve","tennis serve biomechanics","biomechanics","mult i rigid body modeling","simulation" and so on.It consults the liter ature at home and abroad as well as the relevant treatises.The p resent situation of the research on the technique of the upper lim b whipping movement in the tennis serve and the application of computer technology in the field of sports are studied,which lays a theoretical foundation for this study.2)The main experimental measurement is that a total of 6 tennis elective athletes in Liaocheng University Sports College(age 19.5 ±0.5 years,height 179.5 ± 2.5cm,body weight 69 + 6kg)were selected as the most experimental subjects.Using two JVC-GC-PX100 camera models of 6 athletes serve were collected synchronously by the light emitting diode,clip,joint calibration Simi Motion9.1,output kinematic data,the 6 test of far mobilization of elbow joint,wrist joint angle time curve,velocity curve end head with time the changes were obtained to serve the kinematic analysis.3)The method of software engineering:Influence of power factor on serving speed of tennis serve is analyzed.The influence of different serve techniques on the speed of tennis service is analyzed,which is mainly manifested in the changes of wrist angle and elbow joint angle.By using the method of Matlab GUI programming,will be simplified as 3 rigid bodies,write the angle of elbow joint and wrist joint angle and the inertia of the program,the simplified rigid body of general mechanics analysis,lists the relationship between the joint angle and moment of inertia,calculation program between the elbow joint and wrist joint angle angle and rotation inertia,elbow angle inertia,wrist angle rotation inertia curve obtained,kinematics analysis of the data integration,further discussion on the upper links serve,serve in the analysis of upper limb link whip.3)The results of 6 athletes were feedback and adjusted accordingly,and training for one month,then the service data were collected again,comparing the results before and after.Results1)Serve the elbow 6 tennis players have two kinds of angle change,the elbow angle decreases first,here is the racket link energy storage;the elbow angle increase stage,the swing.There are two kinds of changes in the wrist angle,which decrease and increase,and the reduction stage is the storage energy.2)6 athletes have different ways of serving.The main differences are in the stage of the beat,the angle of the elbow and the angle of the wrist.Through correlation calculation and data obtained by Simi Motion,it is found that the speed of the racket’s end is positively correlated with the kinetic energy change involved in the end of service.Conclusion1)Through the analysis of kinematics and computer aided analysis,it is known that in addition to increasing the muscle strength,the service speed can also be improved by changing the technique of serving.Improving motion technology is the main task of computer aided technology.2)The change of the speed of the joint point displacement of the tennis serve is known,when the tennis serve has the upper arm to the forearm,the momentum transfer from the forearm to the head,and the turn of the upper limb to ensure the momentum transfer in order to make the end get a greater speed.According to the results of computer aided analysis,braking is conducive to the transfer of momentum moment and increase the terminal speed,so the reasonable whip action has the braking of the proximal link.3)In the analysis of the angular velocity change of the tennis serve,there is a transfer of the moment of momentum,but by calculating its external torque is not zero,the local link is not satisfied with the conservation of momentum moment.The calculation of the reduction of momentum moment and the change curve of the moment of inertia find that the relative braking is beneficial to the transfer of momentum moment,which makes the end get more momentum moment,and the further description of the whip brake is relative braking.4)When the ball hits the ball,every link in the upper limb is in the same direction,and the moment of inertia at the end of the ball is increased.According to the rotational kinetic energy theorem,we need to get higher batting speed,increase rotational inertia or increase angular velocity,and change the rotational inertia by changing the radius of rotation.Angular velocity is mainly increased by muscle strength.5)The elbow joint angle and wrist angle affect the rotational inertia of the upper limbs.The angle of elbow joint is changed by the work of serving the ball and the angle acceleration of the elbow is changed.The angle of the elbow increases,the radius of the end is increased,the moment of inertia of the end increases,and the end produces a larger rotational kinetic energy.Combined with computer aided analysis,the best hitting angle is gradually increasing in elbow angle and wrist angle.