EMG

Electromyography (EMG) is the recording of the electrical signal that comes from a muscle. As skeletal muscle works to perform a task the electrical activity increases. The EMG signal is recorded by placing electrodes on the surface of the body, above the muscle. The electrodes are connected to an EMG amplifier and the signal is displayed and recorded.

EMG amplifiers are capable of amplifying very low level electrical signals that come from the muscle while eliminating other signals. Telemetry systems allow researchers to record EMG signals from subjects that are exercising. A telemetry system is a device worn by a subject that sends data back to a receiving module. Telemetry allows the subject to have complete freedom because there are no cables connecting them to the recording equipment.

EMG can be recoded from any skeletal muscle, including facial EMG. This allows researchers to monitor how a subject responds to certain types of stimulation. It is also used to record the startle response from a subject that has received a loud noise through a set of headphones.

Physiologists look at the amplitude of the EMG signal as well as the frequency. Software programs allow researchers to automatically review the signals in real-time.