A training device includes a motor including a sensor member connected therewith which is electrically connected to a control unit which controls the motor via commands from a user. A torque output unit is connected with an output shaft of the motor and transfers a resistant force to users and to transfers the force from the user to the motor. The torque output unit includes a speed reduction unit and a tension unit so as to transfer proper force between the motor and the users. The users exercise muscles by the vibration provided by the motor which rotates to-and-fro repetitively.