Abstract: A playing field surface for active running and body contact type sports, such as football and the like, is formed of a stabilized, flat base surface covered by an underpad, over which is laid a synthetic pile fiber carpet. A covering of sand-like granules is applied upon the carpet to substantially fill the spaces between the fibers. The underpad is made of reclaimed rubber, sliver-like small particles which are bonded together into a thick, water pervious mat. The lower surface of the underpad is formed with widely and regularly spaced apart, dimple-like indentations and downwardly extending, rounded hills that contact the base surface. The hills are separated by rounded indented ridges which are of a lesser depth than the indentations. Each of the indentations is surrounded by a number of hills and ridges to provide resilient dome-like, interconnected, downwardly open pockets in the bottom surface of the underpad.