Ph.D Thesis

Ph.D StudentLangzam Eran
SubjectElectro-Mechanical Studies of Muscle Activity Enhanced by
External Stimulation
DepartmentDepartment of Biomedical Engineering
Supervisors PROFESSOR EMERITUS Joseph Mizrahi
Full Thesis textFull thesis text - English Version


Hybrid muscle activation is a modality used for muscle force enhancement, in which muscle contraction is generated from two different excitation sources: volitional from the CNS and induced, by means of external electrical stimulation (ES). The objective of this work was to analyze the parameters involved in hybrid muscle activation, specifically the partition between the volitional and induced components within the overall muscle force. The study was undertaken on the human Tibialis Anterior (TA) muscle under two activation profiles: static and dynamic isometric contractions. The trials consisted of the following activation modes: ES-activation alone, volitional alone and hybrid. A computational algorithm, based on the muscle EMG and static or dynamic calibrations, was developed to dissociate the volitional component from the overall force. The results for the static profile provided definition of 'working-lines' that relate between the volitional/induced torque shares and the overall output torque, and indicated a range of stimulation intensities with an enhanced ES effect. The dynamic results indicated the quantitative relations between decrease in the volitional torque and the required increase in ES enhancement, and also demonstrated which ES intensity pattern is required to produce a desired overall torque output. The results of this work have direct implications on the development of hybrid muscle activation rehabilitation systems for the enhancement of weakened muscles.