Abstract: A treadmill has tread comprised of slats running as a loop between a front roller and a rear roller. The tread is comprised of multiplicity of slats, each comprising a base and a cover which is detachably or permanently attached to the base. The base provides structural strength to support the weight of a user running on the treadmill. The cover of each slat is non-structural and presents to a user's foot one of several surface textures, such as simulated turf grass, simulated outdoor track cobbles, or gym mat. In each slat, the cover has a Shore A Durometer hardness of 50-70, which hardness is less than the hardness of the base.