In 1966, San Diego civil lawyer David Pain began organizing what he called "masters miles" at indoor and outdoor track meets, and set the minimum age at 40. He and others soon launched the U.S. National Masters Championships, where everyone 40 and over competed together. The inaugural meet, at San Diego's Balboa Stadium, was held July 19–20, 1968, and attracted 186 competitors. The second U.S. masters nationals, July 3–6, 1969, drew 200 athletes and introduced 10-year age groups for all events.