Bicycle Motocross, or BMX, is an extreme cycling sport that started in the 1960s with children on bicycles imitating the tricks performed by older motorcycle racers. The sport has since taken off and now, forty years later, it will debut at next month\'s Olympics in Beijing. For producer Liu Enming, Elaine Lu has more on the U.S. Women\'s BMX Olympian. 1960s, Beijing, Bicycle, BMX, California, Chula, cycling, Diego, enming, Motocross, motorcycle, news, Olympian, racers, San, sport, U.S., Vista, voa, Women's