A treadmill apparatus having a non-motorized tread, a sensor for sensing a parameter indicative of the tread speed, and a controller operatively connected to an angle adjustment mechanism to increase and decrease the angle of the tread. During operation of the treadmill, the controller compares the speed of the tread to a target speed, and based on the comparison, adjust the angle of the tread so that the operator's weight will adjust the speed of the tread.