A treadmill safety key is a safety device that must be connected to a treadmill in order for the treadmill to operate. The safety key acts as a circuit breaker to prevent injury.
A treadmill's motor does not function unless the safety key is connected to it. The inserted safety key is generally attached to the user by a cord. The safety key prevents injury by disabling the treadmill belt motor if the user steps or falls away from the machine. The safety key also helps prevent children from operating the machine. There are a few different types of treadmill safety keys, the most popular type being magnetic.