A treadmill includes a frame, a deck assembly, at least one deck deflection sensor, and a control system. The deck assembly is supported by the frame. The deck assembly includes a longitudinally extending deck, at least first and second rollers, and a belt positioned about the deck and the first and second rollers. The deck deflection sensor is coupled to the deck. The deck deflection sensor is a contactless displacement sensor including an electrical intermediate device and an aerial. The control system is operably coupled to the at least one deck deflection sensor.