Load sharing among muscle and dynamic relationship between multi-muscle EMG's and isometric joint moment

An in vivo and noninvasive technique was developed to determine the human elbow extension moment distribution among the three heads of the triceps and the anconeus muscles, and to model the relationship between the multi-muscle EMG's and the joint extension moment dynamically. The static M-wave and joint moment relationships for each head of the muscles was used to calibrate the EMG signals and determine load sharing during voluntary tasks. Results showed that the medial head triceps was the prime elbow extensor and the anconeus contributed significantly at low levels of the extension moment. Both load sharing and the model parameters varied with the joint extension moment. Contributions of the medial head triceps and anconeus decreased with the mean joint moment, while those of the lateral and long heads of triceps increased with it.