There is no electricity. Treadmill is the simplest family fitness equipment, which can achieve the effect of electrification by attracting internal circuits. The safety switch lock is an automatic protection device of the treadmill, and the safety lock socket is electrified. When running, it is necessary to clamp the clip connected with the safety lock on the clothes. Once the safety lock is pulled out in use, the operation machine will stop immediately to protect the safety of users.