Hurdling is the act of running and stepping over an obstacle at speed. In the sport of
athletics, hurdling forms the basis of a number
track and field events which are a highly specialized form of
obstacle racing. In these events, a series of barriers known as
hurdles are set at precisely measured heights and distances which each athlete must pass by running over. Failure to pass over, by passing under, or intentionally knocking over hurdles will result in disqualification. Accidental knocking over of hurdles is not cause for disqualification, but the hurdles are weighted to make doing so disadvantageous.