Abstract: A laminated treadmill deck insert includes a wear surface formed of a phenolic impregnated paper laminated to an isocyanate resin bonded MDF insert core less than about 5/16 inch thick. A low moisture content isocyanate resin bonded wood fiber MDF core enables dimensional stability and high internal bonding strength even at reduced insert thicknesses. The deck insert is disposed on a support deck adjacent the upper run of an endless treadmill belt. The insert is provided with wear surfaces on each broad side and is easily removable and reversible to expose the second wear surface.