United States Olympic Trials (track and field) fill out the field. Since 1972 there have been a minimum of 24 entries in any event, with the popular sprint events 100 meters, 200 meters, 400 meters and 110 meter hurdles having a minimum of 32 entries. Since 1992, athletes achieving the "A" standard are funded to attend the Olympic Trials, while "B" standard athletes have to pay their own way to the meet. Unlike many other countries, who have a selection committee, the selection to the United States Olympic Team is exclusively by results on the track. It's "do or die" in the prescribed event. If two or
All-weather running track All-weather running track An all-weather running track is a rubberized artificial running surface for track and field athletics. It provides a consistent surface for competitors to test their athletic ability unencumbered by adverse weather conditions. Historically, various forms of dirt, grass, sand and crushed cinders were used. Many examples of these varieties of track still exist worldwide. Starting in the late 1950s, artificial surfaces using a combination of rubber and asphalt began to appear. An artificial warm-up track was constructed for the 1956 Summer Olympics in Melbourne, Australia. During the 1960s many of these tracks were constructed; examples still exist