Practical to Demonstrate Electromyographic Changes Associated With Phenomena of Fatigue Due to Isometric Exercise

Purpose of the study: Teaching the physiology of motor unit recruitment as a strategy for force generationand changes in the recruitment patterns as a consequence of fatigue.Methodology: A protocol was designed to study fatigue developed as a consequence of graded isometricexercise and the surface electromyographic (sEMG) features associated with development of fatigue.Main findings: Fatigue can be quantified by reduction in grip force in isometric hand grip. During maximalexercise, sEMG amplitude declined with time as a consequence of fatigue. The sEMG amplitude wasobserved to increase in the case of submaximal exercise representing recruitment of additional motor unitsto compensate for declining force production in fatigued motor units.Conclusion: The proposed practical exercise fulfils the teaching goal of acquainting the students with themotor unit recruitment patterns as reflected in sEMG associated with fatigue development.

An Innovative Method to Demonstrate Nerve – Muscle Physiology Experiments Using Finger Muscle Twitch Recording in a Human Subject

Purpose of the study: Demonstration of nerve-muscle experiments play a vital role for teaching Physiologyto undergraduate medical students. In recent days, procuring frogs for the conduction of these experimentshave become a major concern. Therefore, we have designed an innovative method to carry out nerve-musclePhysiology experiments in human subjects.Methodology: We designed a simple and feasible method to demonstrate the effect of increasing strengthof stimuli, two successive stimuli and tetanic stimuli on human finger muscle twitch response.Main findings: Results of four nerve-muscle experiments performed in a human subject using an innovativemethod has been presented in this article. First, recording of finger muscle twitch by ulnar nerve stimulation.Second, effect of subthreshold, threshold, maximal and supramaximal stimulus with increase in the strengthof stimulus. Third, effect of two successive stimuli on finger twitch response. Four, effect of tetanizingstimuli on finger twitch response.Conclusion: Here we propose a simple innovative practical for effective demonstration of nerve-musclePhysiology experiments using human subject for under-graduate teaching.