How it works
Women start from blocks and negotiate ten 2ft 9in (83.8cm) hurdles spread over a 100m straight. A reaction time – measured by sensors in the starting pistol and on the blocks – of less than 0.1 is deemed a false start and runners will be recalled, and the responsible athlete disqualified.
Once the race is under way there are 13m to the first hurdle, 8.5m between hurdles thereafter, and 10.5m from the final hurdle to the finish. The hurdles are knocked down easily if touched, which allows the athlete to continue the race even if she collides with them. But a runner can be disqualified if she steps out of her designated lane.
The event evolved from wooden barriers being placed along a 100 yard stretch, in England during the 1830s. The inaugural Women’s World Games of 1922 featured the 100m hurdles, and a slightly truncated event made its first Olympic appearance – at 80m – in 1932. The distance was increased to 100m at the 1972 Olympics.
Did you know
Until 1935, athletes were disqualified for knocking over three hurdles or more and records were only registered if an athlete cleanly negotiated all the hurdles.
It’s a sprint, so the USA sets the benchmark. Germany, Bulgaria, Russia, Sweden, Canada and Jamaica are also strong.
The Bulgarian set four world records and struck Olympic gold in 1988. Her final mark – 12.21, also in 1988 – was finally broken in 2016 by USA's Kendra Harrison.