Use of electromyography in studying human movement
Electromyography involves recording the action potentials that activate skeletal muscle fibres. As early as the 1600s, scientists knew that the electromyography (EMG) signal existed (Basmajian and De Luca, 1985), but they were limited by a lack of appropriate equipment to detect the signal. Thus, the science of recording EMG signals probably received its greatest impetus from the related technique of electrocardiography (ECG), which involves detecting the electrical activity of the heart. With the advent of the electrical equipment needed to detect the EMG signal in the early 1900s, physicians began using qualitative interpretation of EMG to diagnose neuropathies and various neuromuscular disorders. Quantitative EMG, however, was not commonly used until the 1950s and 1960s, when the development of electronic integrators allowed researchers to more easily quantify the amplitude of the EMG signal (de Vries, 1966, 1968). With gradual improvements in EMG equipment and signal processing techniques, EMG has evolved to the point where it is now considered to be a very useful biological signal that contains a great deal of information regarding the state of the neuromuscular system (De Luca, 1997).