There are two types of field events: jumps and throws. In jumping competitions, athletes are judged on either the length or height of their jumps. The performances of jumping events for distance are measured from a board or marker, and any athlete overstepping this mark is judged to have fouled. In the jumps for height, an athlete must clear their body over a crossbar without knocking the bar off the supporting standards. The majority of jumping events are unaided, although athletes propel themselves vertically with purpose-built sticks in the pole vault.