If the runner has not turned around and fled full speed to the base, the fielder should continue running right at him. A fielder running forward will ALWAYS catch a runner dancing backward. If you go full speed, the runner has two choices: be out, or run away FAST. If the runner jukes, leave spike marks up his jersey (metaphorically). But if he commits, turns, and finally is himself going full speed back to his base of origin, he is an easy out on a good throw.
Submitted by: Jeff Smith