The setting of zombies speed " Sprinters " are glitched a bit, becouse they sprint fast, okay, but they have same movement speed as a player, so player cant run away from them or loose in a corners of city. By the way, when they reach you they just STOP like on a millitary command and slowly bite you, then again they sprint very fast, and when they reach you, they stop and slowly bit you. It should be fixed, they should have more rage, like in really 28 days later movie