By Mary Milliken RIO DE JANEIRO (Reuters) - BMX cyclists might have the fastest first two seconds of any event in the Olympic Games - coming out of a gate on an eight-meter high wall and going from zero to 56 km per hour in just two beats. For American racer and two-time Olympian Connor Fields, those two seconds account for 75 percent of his training and often determine if he can win the race which usually lasts less than 40 seconds. "We work our butts off and I think we have one of the most difficult sports in the Games because we require so many different skills," said Fields while training in California before he heads to Rio de Janeiro for his event on Aug. 17-19. More...