The men's and women's events at London 2012 both start with a seeding phase: each rider runs the track once to determine the seedings, which ensures that the fastest riders don’t meet before the final.
The women progress straight to the semi-finals and the men’s event continues with the quarter-finals, which are held over five runs, with points for places on each run. After three runs, the best two riders from each quarter-final progress to the semi-finals. The remaining riders compete in the final two quarter-final runs and the best two from each quarter-final also progress to the semi-finals.
From here, the semi-finals in both the men’s and women’s events follow a three-run format. The top four riders from each semi-final advance to the final, where the medals are decided over one run.
Find out more about the Mens' BMX Cyling and Women's BMX Cycling competitions at the Olympic Games on the International Olympic Committee website.