This study analyzed the difference between using a downward breaststroke kick and a horizontal breaststroke kick in a sample of world class elite swimmers.We compared average muscle activity of the gluteus maximus,qua...This study analyzed the difference between using a downward breaststroke kick and a horizontal breaststroke kick in a sample of world class elite swimmers.We compared average muscle activity of the gluteus maximus,quadriceps femoris(vastus medialis and rectus femoris),hamstring/long head of the biceps femoris,gastrocnemius medialis,rectus abdominal,and erector spinae when using the downward breaststroke kick technique.We find that when this sample of swimmers utilized the downward breaststroke kick,max speed and velocity per stroke increased,measured by 12,788 EMG samples,where the results are highly correlated to duration of the aerodynamic buoyant force in breaststroke kick technique.The increases in performance observed from measuring the world class elite swimmers is highly correlated to the duration of the kick aerodynamic buoyant force.Among this sample of elite swimmers,the longer a swimmer demonstrates a buoyant force breaststroke kick,the lower the time in a 100 breaststroke.展开更多
Neural interfaces based on surface Electromyography(EMG)decomposition have been widely used in upper limb prosthetic systems.In the current EMG decomposition framework,most Blind Source Separation(BSS)algorithms requi...Neural interfaces based on surface Electromyography(EMG)decomposition have been widely used in upper limb prosthetic systems.In the current EMG decomposition framework,most Blind Source Separation(BSS)algorithms require EMG with a large number of channels(generally larger than 64)as input,while users of prosthetic limbs can generally only provide less skin surface for electrode placement than healthy people.We performed decomposition tests to demonstrate the performance of the new framework with the simulated EMG signal.The results show that the new framework identified more Motor Units(MUs)compared to the control group and it is suitable for decomposing EMG signals with low channel numbers.In order to verify the application value of the new framework in the upper limb prosthesis system,we tested its performance in decomposing experimental EMG signals in force fitting experiments as well as pattern recognition experiments.The average Pearson coefficient between the fitted finger forces and the ground truth forces is 0.9079 and the average accuracy of gesture classification is 95.11%.The results show that the decomposition results obtained by the new framework can be used in the control of the upper limb prosthesis while only requiring EMG signals with fewer channels.展开更多
Our previous study suggested that the subcutaneous muscle displacement caused by joint movements might alter muscle activation patterns and thus affect the classification performance.To further analyze the effect of j...Our previous study suggested that the subcutaneous muscle displacement caused by joint movements might alter muscle activation patterns and thus affect the classification performance.To further analyze the effect of joint movements on the online performance of Electromyography(EMG)Pattern Recognition(PR),this study assessed online classification performance with and without joint movements.EMG signals were recorded from the dominant forearm of 10 able-bodied subjects under two motion scenarios:Hand and Wrist Joints Unconstrained(HAWJU)and Constrained(HAWJC).Sixth-order autoregressive coefficients and four time-domain features were extracted from EMG signals.Linear Discriminant Analysis(LDA)models were trained to perform an online performance evaluation of the limb motions.The experimental results showed that the four online performance metrics:Motion Selection Time(MST),Motion Completion Time(MCT),Motion Completion Rate(MCR),and Online Classification Accuracy(ONCA)were 0.35 s,1.44 s,97.40%,and 82.61%for HAWJU and 0.37 s,1.47 s,89.70%,and 73.57%for HAWJC,respectively.The outcomes of this study indicated that subcutaneous muscle displacement due to joint movements has a positive effect on online classification performance.The absence of joint movements may be a physiological factor contributing to the poor online performance of the EMG-PR of transradial amputees.This study can provide a new perspective for improving the online performance of EMG-PR for transradial amputees.展开更多
Bilateral rehabilitation systems with bilateral or unilateral assistive robots have been developed for hemiplegia patients to recover their one-side paralysis.However,the compliant robotic assistance to promote bilate...Bilateral rehabilitation systems with bilateral or unilateral assistive robots have been developed for hemiplegia patients to recover their one-side paralysis.However,the compliant robotic assistance to promote bilateral inter-limb coordination remains a challenge that should be addressed.In this paper,a biomimetic variable stiffness modulation strategy for the Variable Stiffness Actuator(VSA)integrated robotic is proposed to improve bilateral limb coordination and promote bilateral motor skills relearning.An Electromyography(EMG)-driven synergy reference stiffness estimation model of the upper limb elbow joint is developed to reproduce the muscle synergy effect on the affected side limb by independent real-time stiffness control.Additionally,the bilateral impedance control is incorporated for realizing compliant patient-robot interaction.Preliminary experiments were carried out to evaluate the tracking performance and investigate the multiple task intensities’influence on bilateral motor skills relearning.Experimental results evidence the proposed method could enable bilateral motor task skills relearning with wide-range task intensities and further promote bilateral inter-limb coordination.展开更多
文摘This study analyzed the difference between using a downward breaststroke kick and a horizontal breaststroke kick in a sample of world class elite swimmers.We compared average muscle activity of the gluteus maximus,quadriceps femoris(vastus medialis and rectus femoris),hamstring/long head of the biceps femoris,gastrocnemius medialis,rectus abdominal,and erector spinae when using the downward breaststroke kick technique.We find that when this sample of swimmers utilized the downward breaststroke kick,max speed and velocity per stroke increased,measured by 12,788 EMG samples,where the results are highly correlated to duration of the aerodynamic buoyant force in breaststroke kick technique.The increases in performance observed from measuring the world class elite swimmers is highly correlated to the duration of the kick aerodynamic buoyant force.Among this sample of elite swimmers,the longer a swimmer demonstrates a buoyant force breaststroke kick,the lower the time in a 100 breaststroke.
基金This study was funded by the National Natural Science Foundation of China(Grant NO.91948302,U1813209,NO.51875120).
文摘Neural interfaces based on surface Electromyography(EMG)decomposition have been widely used in upper limb prosthetic systems.In the current EMG decomposition framework,most Blind Source Separation(BSS)algorithms require EMG with a large number of channels(generally larger than 64)as input,while users of prosthetic limbs can generally only provide less skin surface for electrode placement than healthy people.We performed decomposition tests to demonstrate the performance of the new framework with the simulated EMG signal.The results show that the new framework identified more Motor Units(MUs)compared to the control group and it is suitable for decomposing EMG signals with low channel numbers.In order to verify the application value of the new framework in the upper limb prosthesis system,we tested its performance in decomposing experimental EMG signals in force fitting experiments as well as pattern recognition experiments.The average Pearson coefficient between the fitted finger forces and the ground truth forces is 0.9079 and the average accuracy of gesture classification is 95.11%.The results show that the decomposition results obtained by the new framework can be used in the control of the upper limb prosthesis while only requiring EMG signals with fewer channels.
基金The authors thank all volunteers who participated in the study.This work was supported by National Natural Science Foundation of China(Grant No.52005364,52122501)This work was also supported by the Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education(Tianjin University).
文摘Our previous study suggested that the subcutaneous muscle displacement caused by joint movements might alter muscle activation patterns and thus affect the classification performance.To further analyze the effect of joint movements on the online performance of Electromyography(EMG)Pattern Recognition(PR),this study assessed online classification performance with and without joint movements.EMG signals were recorded from the dominant forearm of 10 able-bodied subjects under two motion scenarios:Hand and Wrist Joints Unconstrained(HAWJU)and Constrained(HAWJC).Sixth-order autoregressive coefficients and four time-domain features were extracted from EMG signals.Linear Discriminant Analysis(LDA)models were trained to perform an online performance evaluation of the limb motions.The experimental results showed that the four online performance metrics:Motion Selection Time(MST),Motion Completion Time(MCT),Motion Completion Rate(MCR),and Online Classification Accuracy(ONCA)were 0.35 s,1.44 s,97.40%,and 82.61%for HAWJU and 0.37 s,1.47 s,89.70%,and 73.57%for HAWJC,respectively.The outcomes of this study indicated that subcutaneous muscle displacement due to joint movements has a positive effect on online classification performance.The absence of joint movements may be a physiological factor contributing to the poor online performance of the EMG-PR of transradial amputees.This study can provide a new perspective for improving the online performance of EMG-PR for transradial amputees.
文摘Bilateral rehabilitation systems with bilateral or unilateral assistive robots have been developed for hemiplegia patients to recover their one-side paralysis.However,the compliant robotic assistance to promote bilateral inter-limb coordination remains a challenge that should be addressed.In this paper,a biomimetic variable stiffness modulation strategy for the Variable Stiffness Actuator(VSA)integrated robotic is proposed to improve bilateral limb coordination and promote bilateral motor skills relearning.An Electromyography(EMG)-driven synergy reference stiffness estimation model of the upper limb elbow joint is developed to reproduce the muscle synergy effect on the affected side limb by independent real-time stiffness control.Additionally,the bilateral impedance control is incorporated for realizing compliant patient-robot interaction.Preliminary experiments were carried out to evaluate the tracking performance and investigate the multiple task intensities’influence on bilateral motor skills relearning.Experimental results evidence the proposed method could enable bilateral motor task skills relearning with wide-range task intensities and further promote bilateral inter-limb coordination.
