Research Of Muscle Fatigue Recognition Method And Its Application In Isokinetic Strength Training

Strength training by equipment has become one of the mainstream fitness methods in contemporary society which can effectively improve the physical quality of trainers.However,poor training and excessive training frequently happened due to the lack of professional pertinent guidance for ordinary trainers.As a result,it may lead to an insufficient training effect and even cause the muscle injuries.Muscle fatigue is the core indicator for evaluating the training volume is adequate or excessive.Thus,we can effectively avoid the above problems by guiding the trainers to keep exercising until the targeted muscles are moderately tired.This paper thoroughly studied the methods of exercise-induced muscle fatigue recognition in isokinetic exercising,proposed the personalized isokinetic strength training guidance model based on the muscle fatigue recognition methods and the sports theory,thus developed the personalized isokinetic strength training instructing system,and finally constructed the isokinetic equipment based on oscillating hydraulic cylinder.This study is committed to provide more targeted,safer and efficient strength training guidance and equipment,and the details are as follows:1.A isokinetic fatigue experiment on isokinetic knee joint was carried out to obtain the subjective and objective fatigue information for evaluating muscle fatigue.During the experiment,the RPE(Rating of Perceived Exertion),the s EMG(surface electromyography)of 6 targeted muscles and the maximum muscular torque were collected in real time.Among them,the maximum muscular torque change data which extracted from 2-speed training provided the data basis for personalized training intensity setting.Further processing and statistical analysis of the subjective fatigue RPE(Rating of perceived exertion)and s EMG signals were made,and the results were as follows:(1)The RPE gradually increased with the process of strength training,and it was linearly related to the training time.(2)Two nonlinear dynamic indexes extracted from s EMG signal of 5 targeted muscles except SE(Semimembranosus):the SDE(Spectral Density Entropy)and the WE(Wavelet Entropy),which had significantly negative correlation with RPE that can be used to identify muscular fatigue during the strength training.2.Dynamic muscle fatigue recognition based on the subjective and objective muscular fatigue information was studied.Due to the time-space characteristics of s EMG signal,a new CNN(Convolutional Neural Network)model was set up to extract and classify the fatigue features of the target muscles' s EMG in the isokinetic strength training of knee joint based on the deep learning theory.At the same time,based on the characteristic signals of s EMG extracted in the second chapter which can identify fatigue,2 fatigue identification models were built according to the traditional fatigue classification methods: the Multi-SVM(Multi-Support Vector Machine)model and the Multi-LDA(Multi-Linear Discriminant Analysis)model.And then,the fatigue identification models were compared with each other.The results showed that CNN model had higher accuracy and less time delay,which can be used to identify dynamic muscular fatigue in real time.3.According to the needs of multi-goals improvement in actual strength training,such as "speed strength","absolute strength","endurance strength",the paper constructed a real time guidance model for personalized isokinetic training which inputs training goal and outputs the training load,speed,group number and time.The model was based on the strength training theory guidance of sports physiology and combined with CNN dynamic muscular fatigue recognition model.After that,a framework was established according to the trainer's using process.Then,a personalized isokinetic training system was built based on Android system.4.An isokinetic damping device was designed according to the basic principle of oscillating hydraulic cylinder.In light of the needs of large range resistance output,rapid change of resistance and personalized training loads in isokinetic training,a new isokinetic control strategy was realized.Then,the new isokinetic knee joint trainer and the shoulder rotary trainer were designed and the prototype is made based on the human body size of Chinese adults.Finally,the training effect of the new isokinetic equipment with the traditional equipment was compared through the strength training evaluation experiment,the feasibility and scientificity of the new isokinetic equipment were verified in several dimensions,which laid the foundation for further expanding the isokinetic training of the whole body joint muscles.