An exercise device includes a frame with a deck cooperating with the frame. The deck and frame cooperate with an endless belt having an upwardly exposed exercise section upon which an exercising user may rest or exercise. An impact absorbing mechanism cooperates with the frame and the deck and is configured to adjustably cushion the impact of a user upon the exercise section of the endless belt. The impact absorbing mechanism includes at least cushioning member and at least one spring at least partially surrounding a portion of the at least one cushioning member, wherein adjustment of the impact absorbing mechanism is achieved by replacing at least one of the at least one cushioning member and the at least one spring with at least one of another cushioning member and another spring.