An EMG machine is a piece of equipment used to perform an electromyography (EMG) test. This procedure can detect neuromuscular damage by measuring muscular responses to nerve stimulation. An EMG test starts when the administer inserts a needle electrode directly into the muscle to record electrical activity. To complete the function, the EMG device transfers the electrical activity from the muscle to an oscilloscope and an audio amplifier for examination and evaluation. The EMG machine records electrical activity when the muscle is at rest, in slight contraction and forceful contraction.