Olympics-Cycling-Trott extends lead in omnium as Brits dominate again

By Martyn Herman RIO DE JANEIRO, Aug 16 (Reuters) - Defending champion Laura Trott extended her lead at the top of the Olympic track cycling women's omnium on Tuesday after posting the second fastest time in the two-lap time trial. After four of the six events the British rider is 12 points ahead of Belgium's Jolien D'Hoore and 16 better off than American Sarah Hammer. Trott is bidding for a second gold medal at the Rio Games, having already won the team pursuit in a world record time. She also won both events in London. On Monday Trott, 24, finished second in the scratch race before winning the individual pursuit and elimination events. The two remaining events are the flying lap and the points race. The track programme concludes at the Rio velodrome on Tuesday when, as well as the omnium, the women's sprint and men's keirin will also be decided. Britain have won four of the seven titles so far and could be set for more with Rebecca James and Katy Marchant both into the semi-finals of the sprint. James is up against Elis Ligtlee of the Netherlands, who beat her to gold in the kierin, while Marchant faces twice world champion Kristina Voegel of Germany. Voegel, at 25, is the oldest of the four qualifiers, who have an average age of 23. (Reporting by Martyn Herman; Editing by Clare Lovell)