The men's 100m final is the premier event at the Olympics and we have put together five things you should know before the big race.
1) The main event
The 100m final starts at 8.50am this morning and an estimated 1billion TV viewers are expected to watch.
Never before has the eight man line-up been so strong when Usain Bolt, the defending Olympic Champion and Yohan Blake, his training partner and World Champion, go head-to-head.
Bolt, who clocked 9.58sec at the 2009 World championships in Berlin, cruised into the Olympic semis with a time of 10.09sec while Blake was a fraction faster at 10sec.
But their times were behind Americans Justin Gatlin (9.97sec) and Ryan Bailey (9.88sec).
Bolt, who reached speeds of 44km/h in 2009 in Berlin, believes it's possible to run the race in 9.4sec but his performances over the last few months suggest the Jamaican is struggling to achieve the same dominance.
He last met Blake at the Jamaican trials and his quiet rival won with the fastest time of the year at 9.75sec.
But even leaving Bolt and Blake aside, five other sprinters have run sub-9.90 times this season in Gatlin, Asafa Powell, Keston Bledman, Bailey and Tyson Gay.
The depth of talent is so great that the Olympic final could see all eight sprinters run under 10sec for the the first time.
2) Usain Bolt infographic
If you've ever wondered how you would go in a 100m race against the world record holder then try our Bolt infographic here.
Just type in your estimated 100m time and see where you would finish in a one-off race with the current Olympic champion.
3) Evolution of the 100m event
We also have an Olympic infographic which shows how the 100 metre dash has evolved over the last century. Follow five historic Olympians here as they run their Gold Medal pace.
4)The main contenders
Usain Bolt is 1.96m tall and weighs 93kg.
The 25-year-old Jamaican played cricket for his school as his height made him a natural fast bowler. His cricket coach recognised he was also quick on his feet and suggested he try sprinting. The rest is history.
Bolt said he tries to relax on race day. "I think about other stuff, maybe cars or something. If you think about racing too much you may just lose it a little bit," he told the BBC.
The sprinter revealed he also has some unusual nutritional preparation. He admitted that during his record runs at the 2008 Beijing Olympic Games he was eating up to 15 chicken nuggets at least once a day.
Yohan Blake is 1.8m tall and weighs 76kg.
The 22-year-old Jamaican is also a keen cricketer who likes to keep up with the performances of the West Indies team. No doubt he'll be tuning into the test match against the Black Caps.
He lists 100m sprinter Asafa Powell as his hero and he became the youngest person ever to break the 10 sec barrier aged just 19 and 197 days.
5) Is there a limit to athletic performance?
So will the 100m record keep tumbling as people get fitter and technology takes off or is there a limit to human performance? This article is packed with everything you need to know about the topic.
- Herald Online