Muscle Contraction

The deliberate tensing of a muscle group that generates an electrical signal (electromyographic or EMG signal) detectable by surface electrodes. In assistive technology, intentional muscle contractions serve as input signals for controlling devices when traditional input methods like keyboards, mice, or joysticks are not usable. Even individuals with very severe physical disabilities who retain voluntary control over a single muscle — such as a facial muscle, eyebrow, or jaw — can use contractions as binary input events to operate wheelchairs, computers, and communication systems through appropriately designed interfaces.