IZU (Reuters) - Reigning champion Laura Kenny's hopes of winning a third successive Olympic gold medal in omnium suffered an early blow as she was involved in a huge pile-up in the opening scratch race at the Izu Velodrome on Sunday.

The British rider, winner in 2012 and 2016 and looking for her sixth Olympic track cycling gold in total, was caught up in the huge crash near the end of the 30-lap race -- the first of four events that will decide gold.