Abstract: An animal running surface composition and optimization technique is described. The surface provides a firm in-place foundation layer above which is spread a surface layer. The surface layer intermixes earthen material and rubber particles which may be sized from one-quarter to three-quarters of an inch. These particles may also be shredded rubber from scrap tires to assist in waste disposal. The ratio of the amount of rubber particles to earthen material in the surface, the size of the rubber particles, and the depth of the surface layer can be varied to optimize the surface for particular uses ranging from horse or equestrian tracks to dog tracks to arenas, etc. Several other variations such as the avoidance of organic material, removal of any metallic materials, and inclusion of other layers are also provided for. The present invention provides resiliency, optimizes water use, is porous for drainage, and can be reasonably constructed, among other advantages.