EMG (electromyography) records the movement of our muscles. It is based on the simple fact that whenever a muscle contracts, a burst of electric activity is generated which propagates through adjacent tissue and bone and can be recorded from neighboring skin areas. The lower motor neurons are the actual instigators of muscle movement, as they innervate the muscle directly at the neuromuscular junction. This innervation causes the release of Calcium ions within the muscle, ultimately creating a mechanical change in the tension of the muscle . As this process involves depolarization (a change in the electrochemical gradient), the difference in current can be detected by EMG.