ABSTRACT
Electromyography has been used as a tool in research and in applied areas to tell us many things about the activity of muscles during any movement of humans or animals. Neurologists use electromyogram (EMG) recordings to determine the integrity of neural pathways, neurophysiologists use EMGs to test control and reflex mechanisms and identify synergistic patterns, clinicians use EMGs in a wide range of pathologies to identify atypical motor patterns, biomechanists and bioengineers use EMGs in a wide variety of muscle models and to actuate myoelectric prostheses, and ergonomists use EMGs as indicators of stress and fatigue. There is considerable overlap between their techniques and interpretations. However, unfortunately there is no common and accepted terminology and standards, which has led to misleading and erroneous terms and units. The pmpose of this chapter is to provide the background that is common to most of these users and focus on the understanding that ergonomists require for their interpretations. The chapter will cover the biophysical basis of electromyography, important considerations regarding problems of recording, various processing techniques, and interpretations related to fatigue and muscle tension.
